Remove event titles text shadow: looks ugly if the text is black

fc-event text-shadow should not be defined inside FullCalendar. On white text it looks nice, not on black and other colors.
FullCalendar should stay neutral.

With text-shadow:
![With text-shadow](http://img15.hostingpics.net/pics/777559ScreenShot20130327at113811PM.png)

Without:
![Without text-shadow](http://img15.hostingpics.net/pics/138643ScreenShot20130327at113908PM.png)