GTime
The secs() method now returns a const reference.
GTimeReference
The load constructor and the read() and write() methods take
a const reference instead of a pointer.
GGti
The read() and write() methods now use references instead of
pointers. The clobber argument in the save() method is passed
as const reference.
GEbounds
The read() and write() methods now use FITS references instead
of pointers. The clobber argument in the save() method is passed
as const reference.
GPhoton
Add mcid argument to Photon constructor (defaults to -1).
