Add direct download version of PaintCode 1.3.4

PaintCode was available through a recent MacHeist bundle, where it was
made available as a direct download for the first time -- the normal
distribution method is Mac App Store. This cask can be used for non-MAS
owners of PaintCode to access the direct download version.
Changed PaintCode to use version latest

Also changed to from 'sha256' to 'no_checksum"
Merge pull request #4030 from mauricerkelly/paintcode-direct-download

Add direct download version of PaintCode 1.3.4