USER: New physics class included for testing (will become base for future physics class). Used for testing to varify the rest of the code. A bug in the reconstruction class was found and fixed (Kinetic Energy actually was including the masses, oops!). Now a missing mass calculated off the pi0 comes out to the proton mass (exciting!)... Many changes were done to the base tree managers to make them more general (and more will be done as well). Routines were added to GoATTreeManager to allow for the physics classes to loop over entries in trees defined in the GoAT classes, and those defined by Acqu classes. The tree managers now have new names to reflect their new class names.
Fixing file PPi0.cc from last commit, a single line (which handles the beam 4vector) was erased. Follow last commit message for full update.
USER: New PPhysics class which works below example PPi0 class. PPi0 currently fills a set of histograms for eta and pi0 (eta included now for testing) and writes these to a histogram file. No user controls in config file.
USER: Added some eta class, not to be used as the general eta class, however it exists currently for testing purposes and verification of eta physics reconstruction. WARNING: input and output file are no longer declared in config file but are done via command line. This is prep for a future commit which will include a script to handle running goat (or physics routines) over multiple files.
USER: Added new functionality to perform charged particle and meson reconstruction over specific theta region only! Useful for the eta group, otherwise shouldn't *really* be used...
Tree production in physics class

Added first portion of tree production in physics class. This will be done ahead of histograms.
clone trees are private now
changed tree system. introduce new interface class GTree
fixed eventcount in GAcquTree. Make mass private and renamed Set/GetInputMass to Set/GetMass
bugfixes GTree. coreected inline functions in GAcquTree. All Set/GetAcqu* renamed in Set/Get*