Use Go 1.5 vendoring instead of Godeps

Change made by:

- running "gvt fetch" on each of the packages mentioned in
  Godeps/Godeps.json
- `rm -rf Godeps`
- tweaking the build scripts to not mention Godeps
- tweaking the build scripts to test `./lib/...`, `./cmd/...` explicitly
  (to avoid testing vendor)
- tweaking the build scripts to not juggle GOPATH for Godeps and instead
  set GO15VENDOREXPERIMENT.

This also results in some updated packages at the same time I bet.

Building with Go 1.3 and 1.4 still *works* but won't use our vendored
dependencies - the user needs to have the actual packages in their
GOPATH then, which they'll get with a normal "go get". Building with Go
1.6+ will get our vendored dependencies by default even when not using
our build script, which is nice.

By doing this we gain some freedom in that we can pick and choose
manually what to include in vendor, as it's not based on just dependency
analysis of our own code. This is also a risk as we might pick up
dependencies we are unaware of, as the build may work locally with those
packages present in GOPATH. On the other hand the build server will
detect this as it has no packages in it's GOPATH beyond what is included
in the repo.

Recommended tool to manage dependencies is github.com/FiloSottile/gvt.

vendor/github.com/calmh/du/LICENSE

@@ -0,0 +1,24 @@
+This is free and unencumbered software released into the public domain.
+
+Anyone is free to copy, modify, publish, use, compile, sell, or
+distribute this software, either in source code form or as a compiled
+binary, for any purpose, commercial or non-commercial, and by any
+means.
+
+In jurisdictions that recognize copyright laws, the author or authors
+of this software dedicate any and all copyright interest in the
+software to the public domain. We make this dedication for the benefit
+of the public at large and to the detriment of our heirs and
+successors. We intend this dedication to be an overt act of
+relinquishment in perpetuity of all present and future rights to this
+software under copyright law.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
+For more information, please refer to <http://unlicense.org>

vendor/github.com/calmh/du/README.md

@@ -0,0 +1,14 @@
+du
+==
+
+Get total and available disk space on a given volume.
+
+Documentation
+-------------
+
+http://godoc.org/github.com/calmh/du
+
+License
+-------
+
+Public Domain

vendor/github.com/calmh/du/cmd/du/main.go

@@ -0,0 +1,21 @@
+package main
+
+import (
+	"fmt"
+	"log"
+	"os"
+
+	"github.com/calmh/du"
+)
+
+var KB = int64(1024)
+
+func main() {
+	usage, err := du.Get(os.Args[1])
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println("Free:", usage.FreeBytes/(KB*KB), "MiB")
+	fmt.Println("Available:", usage.AvailBytes/(KB*KB), "MiB")
+	fmt.Println("Size:", usage.TotalBytes/(KB*KB), "MiB")
+}

vendor/github.com/calmh/du/diskusage.go

@@ -0,0 +1,8 @@
+package du
+
+// Usage holds information about total and available storage on a volume.
+type Usage struct {
+	TotalBytes int64 // Size of volume
+	FreeBytes  int64 // Unused size
+	AvailBytes int64 // Available to a non-privileged user
+}

vendor/github.com/calmh/du/diskusage_posix.go

@@ -0,0 +1,24 @@
+// +build !windows,!netbsd,!openbsd,!solaris
+
+package du
+
+import (
+	"path/filepath"
+	"syscall"
+)
+
+// Get returns the Usage of a given path, or an error if usage data is
+// unavailable.
+func Get(path string) (Usage, error) {
+	var stat syscall.Statfs_t
+	err := syscall.Statfs(filepath.Clean(path), &stat)
+	if err != nil {
+		return Usage{}, err
+	}
+	u := Usage{
+		FreeBytes:  int64(stat.Bfree) * int64(stat.Bsize),
+		TotalBytes: int64(stat.Blocks) * int64(stat.Bsize),
+		AvailBytes: int64(stat.Bavail) * int64(stat.Bsize),
+	}
+	return u, nil
+}

vendor/github.com/calmh/du/diskusage_unsupported.go

@@ -0,0 +1,13 @@
+// +build netbsd openbsd solaris
+
+package du
+
+import "errors"
+
+var ErrUnsupported = errors.New("unsupported platform")
+
+// Get returns the Usage of a given path, or an error if usage data is
+// unavailable.
+func Get(path string) (Usage, error) {
+	return Usage{}, ErrUnsupported
+}

vendor/github.com/calmh/du/diskusage_windows.go

@@ -0,0 +1,27 @@
+package du
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+// Get returns the Usage of a given path, or an error if usage data is
+// unavailable.
+func Get(path string) (Usage, error) {
+	h := syscall.MustLoadDLL("kernel32.dll")
+	c := h.MustFindProc("GetDiskFreeSpaceExW")
+
+	var u Usage
+
+	ret, _, err := c.Call(
+		uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(path))),
+		uintptr(unsafe.Pointer(&u.FreeBytes)),
+		uintptr(unsafe.Pointer(&u.TotalBytes)),
+		uintptr(unsafe.Pointer(&u.AvailBytes)))
+
+	if ret == 0 {
+		return u, err
+	}
+
+	return u, nil
+}