- Overloaded +, += for pha objects to add them and *= to multiply
by a constant.
- Added version of pha::rebinChannels which allows control of the
method for calculating the new StatError.
- Added pha::shiftChannels to shift channels.
- Added missing write of the DETCHANS keyword/column for type II
PHA files.
- Fixed problem in C wrappers for spectra with arrays containing
identical values.
