Changed the AddAndRemoveMember boards test

Since it broke the Search tests. Weird I know, but these are integration
tests and they're pretty brittle.
Version 0.5.8
Cards.ChangePos. #20.
Pos must be positive. #20.
Lists.ChangePos. #20.
Bumped to 0.5.9.
Fixed Guard error parameter
Upload a file as an attachment. #22.
Upload a file attachments as an array of bytes. #22.
Async versions of file attachment uploads. #22.
Updated .nuspec
This will be a beta
Boards.ChangeLabelName. #23.
Added UpdateComment.
Better UpdateComment, added DeleteAction.

Moved UpdateComment from Cards to Actions & renamed it.
Added DeleteAction.
Added async Actions/ChangeText and Actions/Delete.
Added tests for Actions/ChangeText and Actions/Delete.

Also, moved the ID of the writable list to Constansts.
Removed unnecessary test.
Renamed Change to ChangeText.
Bumped to version 0.5.9

Also fixed a minor xml doc thing.