Detab, pyMAS optional

pyMASreceipt is now optional, and will exit safely if not found.  Also,
broke the formatting via tabs.
Made asn1 optional.
Reworded description, added installs keys

Additionally used PkgCreator from upcoming 0.3.0 AutoPkg release.
Moved cache deletion to after munkiimport
Added blocking applications, installs key
Merge branch 'Development'