Adding support to switch from Textile to Markdown

This adds a checkbox in the advanced section to allow selecting Markdown as the syntax for release notes. It will switch the parameter "notes_type" to 1 if selected, else 0 is being used as before this change.

It is being ignored when change logs are used as release notes.
Added UTF-8 support for release notes
Added support to retrieve release notes from a local file
Merge pull request #7 from dlinsin/release_notes_type

Adding support to switch from Textile to Markdown
Merge pull request #9 from dlinsin/release_notes_from_file

Retrieve Release Notes from a file
Merge branch 'master' of github.com:duhanebel/hockeyapp-plugin into duhanebel-master
[maven-release-plugin] prepare release hockeyapp-1.0.5
[maven-release-plugin] prepare for next development iteration