Support for ${scanFolder} variable

I modified the plugin in order to be able to include all the .js in a folder. In my case, the modules are known only at run time, returned by a web service, so there is no list of dependencies anywhere.

With this change it is possible to include the variable ${scanFolder} like this:

	...
	name : "main",
	deps: [${scanFolder}],
	...

and it will be replaced by the comma separated list of modules found in the folder configured by the fillDepsFromFolder property in the pom.xml configuration:

	<fillDepsFromFolder>${project.build.directory}/requirejs/web/modules</fillDepsFromFolder>

Tests are passing. Looking forward to reading your comments.