-Added new events when window focus is gained and lost.  wcDocker.EVENT_GAIN_FOCUS and wcDocker.EVENT_LOST_FOCUS.
-Modified the z-index level for floating windows so it is easier to put custom content in between.
-Fixed bug with destroyed floating panels coming back.
-Added a new tab to a floating panel will no longer change its size and position.
Update README.md
Merge branch 'master' of https://github.com/WebCabin/wcDocker

Conflicts:
	Build/wcDocker.min.css
	Build/wcDocker.min.js