Need to have extended flags for mouse events to work
Need to have extended flags as one of the modes for mouse events

http://msdn.microsoft.com/en-us/library/windows/desktop/ms685035(v=vs.85).aspx
Clarify documentation on Size() return values.
Suport Grayscale, 216 and 256 color output modes.

Ported from the C version of Termbox.
Allow switching output modes in _demos/output.go.

Right and left arrows switch output mode,
up and down arrows similarly.
Better display colourful output modes in _demos/output.go.
SetOutputMode always sets and returns OutputNormal on Windows.
Fix bold and underline for 256 colour output demo.
_demos/output.go: Sync() after changing output mode.
Fix typo in send_attr.

As noted by the initial committer it seems like a bug.
Remove 'output_mode' use from windows part, fixes compilation.
Support ColorDefault in extended color modes.
Merge branch 'master' of github.com:nsf/termbox-go

Conflicts:
	api_common.go
	termbox.go