Fix exception when selecting keywords in completion list.

Pressing Ctrl+Space and then moving down the list of items in the
completion list would throw a null reference exception when a
keyword, such as 'any', was selected.
Sort completion items.
Merge branch 'master' into monodevelop

Conflicts:
	src/TypeScriptBinding/TypeScriptCompletionData.cs
	src/TypeScriptBinding/TypeScriptCompletionItemProvider.cs