Place SL appended color schemes in User/SublimeLinter

To keep the Package/User directory from becoming unruly,
these files will be stored in Package/User/SublimeLinter now
Add command to clear out (SL).tm-theme files

The command Clear Color Scheme Folder has been added
to easily clean up all the files SublimeLinter has created.
Merge branch 'master' of https://github.com/SublimeLinter/SublimeLinter3