added standard c# .gitignore
added MenuItem-specific event delegate
added TextboxKey delegate and handler hook
namespace (visual studio was complaining)
some typos, formatting
removed redundant update list logic
renamed menu container file to match class name
minor formatting
minor refactoring within the MenuItem hierarchy
added IScreenDimensionsProvider interface
added HierarchicalObject base classes
added IInvalidatable interface
collapsed HandleInput logic down a bit
added default xtor
added support for all 5 mouse buttons
Merge pull request #1 from marzer/master

typos, formatting, gitignore and eventhandlers