Initial Feeds api
Now able to get full feeds. There are a few issues around naming.
Some code style cleanup
Special case JSON _links property.

For some reason, the List Feeds http://developer.github.com/v3/activity/feeds/#list-feeds
API response has a field that starts with an underscore. This also occurs in
the Review Comments API: http://developer.github.com/v3/pulls/comments/#list-comments-in-a-repository
and in the Contents API. http://developer.github.com/v3/repos/contents/#get-the-readme

This commit special cases that one field so we can use the expected CLR
property name. I couldn't find a case where a
JSON response doesn't prefix "links" with an underscore.

Related to #386
Fix names
Added DebuggerDisplay message to Feed
Github documentation updated. Comment no longer relevant.
Removed Extraneous file
Added XML comments to model classes

Added XML comments to model classes: copied feed definitions from github
developer docs
Merge pull request #387 from octokit/haacked/serialization-fix

"_links" JSON field serialization convention fix
Merge branch 'master' into feeds-api
Renamed Links object because json serializer was fixed
Merge pull request #386 from sgwill/feeds-api

Feeds API
Using FAKE 2.10
Merge pull request #390 from forki/Build

Using FAKE 2.10
Support to Create Gists
Remove need for NewGistFile.cs
Initialize Files

Initialize Files to reduce needless setup to create a gist.
Remove suppress attribute
Delete Gist

Add ability to delete gist with test cases.