Development nurpg

- Admin modules are now using the filename's 'ModuleName.admin.php' to denote they are admin modules. This usage is similar to the old "Admin_ModuleName" class structure. 
- PluginManager now activates plugin correctly if __activate() exists and returns true, or if __activate() doesn't exist at all.
- Multiple plugins can be installed via the same upload. This is important for admin modules to be installed with frontend bretheren.
- A new phpDoc comment has been added for Plugin Headers: 'Relation'. This optional comment should be set to either 'parent' or 'child'. Child meaning that it's pid (parent_id) is set to whatever plugin has the same package BUT has a pid of 0 (Absolute parent).