Allowed primary module location to be configured

[joeljeske]

This change allows the primary module (JS & LESS) to have a configured location. This is possible my adding an entry to the modules array in the yeoman config file for the primary module and also having a primaryModule key with the name of the primary module.

Also, modules no longer have to be in subdirectories of their parent modules. When adding a new module, the parent directories will be searched for a module defining file, however, if no modules are found, the primary module will be attempted (regardless if the primary module is in a parent directory of the new module).