DNN-5367: Allow xsl, xslt file extension in module installer.
DNN-5909 GetFoldersByPermissions Performance Improvement
Merge pull request #218 from stephen-lim/Allow_XSL_File_Extension

DNN-5367: Allow xsl, xslt file extension in module installer.  This is a trivial change and was merged directly.
DNN-6136 - Add an additional method to the new interface/controller
DNN-6136 - Add an additional method to the new interface/controller
SOCIAL-3603: fix for Search engine does not pick up post modifications (and probably other social posts).

Also, I made parameter names more indicative of being UTC date/time values.