Add manpage and update Makefile
use mdoc macros in man page
Added the -i option that allows modifier keys that should be ignored to be specified. Such as xbanish -i shift -i control.

Right now, only lower case names are supported, I shall change that.

When debug is enabled, ignored keystrokes are mentioned.
minor cleanups
Merge pull request #10 from johnhill/manpage

Add man page
mention -i option in man page
release version 1.2
Merge branch 'master' of https://github.com/jcs/xbanish