Continuing the builder modularization work.  Created a new SobekCM.Builder_Library project, and moved some classes down into it.  Also, moved another class into the SobekCM.Core project, splitting the old Builder_Source_Folder into two classes, a base class in the SobekCM.Core and another Actionable_Builder_Source_Folder in the SobekCM.Builder_Library project.  Did some general refactoring of all the classes moved (except for the modules themselves which still need proper commenting)
Merge branch 'master' of github.com:MarkVSullivan/SobekCM-Web-Application