feature($custombuild): Generates custom JS build via Grunt task

You can generate a custom build by running the grunt task:

% grunt build:custom [args]

Where args is zero-to-many of:
--traditional
--ui
--jquery
--s3
--modules [mods]

Where mods is a comma-separated list of potential modules:
* paste
* delete
* deleteui
* edit
* all

piece of: #846
feat(Gruntfile): Output the custombuild directory post-build
feat(Gruntfile): Better output for regex capture for custom build
refactor
refactor($custombuild): Cleaner code/logic

The code/function to generate a custom build was just one big function
that I hacked together as a prototype, and it has now been refactored into
something more usable. Command-line API has improved as well.
Merge branch 'develop' into feature/boilerplate
Merge branch 'develop' into feature/boilerplate

Conflicts:
	lib/modules.js
feat: #846 - Boilerplate generates "base" custom builds

Core + Traditional/S3 [+ jQuery]
UI + Traditioanl/S3 [+ jQuery]

[skip ci]
feat: #846 - Boilerplate generates "base" custom builds

Core + Traditional/S3 [+ jQuery]
UI + Traditioanl/S3 [+ jQuery]

[skip ci]
Merge branch 'feature/boilerplate' of github.com:Widen/fine-uploader into feature/boilerplate
fix(Gruntfile): typo in comment
2 spaces -> 4 spaces
Merge branch 'feature/boilerplate' into develop

Conflicts:
	Gruntfile.coffee
	lib/modules.js
Merge branch 'develop' of github.com:Widen/fine-uploader into develop