Make GetAndFlatten public

This allows us to tweak the accepts header and build up
our own requests without duplicating this logic.
Merge pull request #544 from octokit/haacked/make-get-and-flatten-public

Make GetAndFlatten public
Add release notes for 0.4.1
Merge pull request #545 from octokit/release

Add release notes for 0.4.1
Fix typo in release notes
Add All value to the ItemState enum of the IssueRequest class
Add integration test for retrieving all issues.
Removed duplicated integration tests for IssuesClient. Closes #551
Merge pull request #552 from MitjaBezensek/MergeTwoTests

Removed duplicated integration tests for IssuesClient. Closes #551
Merge pull request #550 from MitjaBezensek/Issue517

Fixed the problem with ItemState enum
Add a few missing team and organization APIs
Add UT
Add observable methods
Fix small compilation error
Add missing observable methods
Rename parameter
Merge pull request #553 from andrerod/master

Add a few missing team and organization APIs
Remove trailing slash in ApiUrl
Merge pull request #555 from matt-gibbs/ApiUrls-fix

Remove trailing slash in ApiUrl that causes get of /team/{id]/repos to fail
:lipstick: