Gruntfile.js

* Some grunt stuff...

- Add links to #issue/pull_number and other/repo#issue/pull_number
- Style github issue/pull links as other/repo#issue/pull_number
- Shorten long SHA1 hashes and link them to the commit viewer.
- Fix jshint warnings
- Fix PGP signature not completely removed sometimes.
- List changes and genchanges will now remove all kinds of tag info.
  However, if a commit message starts with "(text) " it will be removed.

* - Fix missing new line
- Style messages that contain lists

* Partially remove unwanted asterisks, remove more commit hashes,
style messages that contain multiple lines, escape italic markdown tag.