Fixes #10, #9

I implemented fixes for mobile zoom in/out and keyboard control problems.

For keyboard controls I implemented two behaviors: the most browser-like (currently active) and hover(), behaving exactly as you plugin previously did, but with honoring form elements (currently commented out).
I think that browser-like approach (element is scrollable with keyboad when it is active/focused) is the best to use, till it provides really native behavior and requires much less code.