Add list & doc commands

This commit fixes #9:

Added `list` command to list availables generators:

	scaffolt --list
	List of available generators in generators:
	* collection
	* view
	
Added `doc` command to display generator documentation:

	scaffolt collection --doc
	
	Documentation for 'collection' generator:
	'scaffolt collection name'
		will create app/models/names.coffee
	
	Dependencies:
	* collection-test
		will create test/models/names-test.coffee