Snapshot of SVN 4610

Changes in this snapshot are focussed on the
FPU (l3fp):

 - Trigonometric functions taking arguments in
   degrees (sind, etc.)
 - Inverse trigonometric functions with arguments
   in radians (asin, etc.) and degrees (asind,
 - Use of these functions in driver code

Please all 48 hours for update to propagate around CTAN.
Joseph Wright