merge README, README.md and INSTALL files
fix tabbing after window has been shaded

trying to switch tabs or drag/drop tabs after the window has been shaded/unshaded,
behaved faulty and would not select tabs.
add correct email addresses and copyright year
infodialog: add GitHub URL to info dialog
release crystal-2.2.1

original release: January 9th, 2013

Changelog:
* Fix tabbing support for KDE-4.9