frame state bits now all defined in nsFrameStateBits.h

FYI, I've just landed bug 960848 which changed nsFrameState from a 
typedefed uint64_t to an enum, and moved all of the #defines that were 
in various frame class header files into a single, pre-processed file, 
nsFrameStateBits.h.  This gives us slightly more type safety.

It also provides the ability to iterate over the frame state bit names, 
which I've used in bug 960899 to write a function that can print out a 
frame's state symbolically.  You can use it like this:

(gdb) p this
$1 = (nsTextFrame*) 0x........
(gdb) p/x mState
$2 = (nsFrameState) 0x0000004080604000
(gdb) call mozilla::PrintFrameState(this)
TEXT_HAS_NONCOLLAPSED_CHARACTERS | TEXT_END_OF_LINE | TEXT_START_OF_LINE 
| NS_FRAME_PAINTED_THEBES | NS_FRAME_INDEPENDENT_SELECTION