move alertify stuff

customize.dist/src/less/cryptpad.less

@@ -1,7 +1,7 @@
 @import "./variables.less";
 @import "./mixins.less";
 
-@import "./alertify.less";
+@import "../less2/include/alertify.less";
 @import "./bar.less";
 @import "./loading.less";
 @import "./dropdown.less";
@@ -10,6 +10,8 @@
 
 @toolbar-green: #5cb85c;
 
+.alertify_main();
+
 html.cp, .cp body {
     font-size: .875em;
     background-color: @page-white; //@base;