Document some common issues with GPG on Mac OSX

Deals with this issue: https://github.com/technomancy/leiningen/issues/1386
fix #1581 - do not try to create an existing directory
Remove citations and change 'voice'

Solutions via people from this issue: https://github.com/technomancy/leiningen/issues/615
Remove inline code blocks
Merge pull request #1576 from Christopher-Bui/patch-1

Document some common issues with GPG on Mac OSX
avoid creating dir only if it is \".\"
Merge pull request #1582 from kumarshantanu/master

fix #1581 - do not try to create an existing directory
Merge remote-tracking branch 'upstream/master'