added script. currently doesn't have hdf5/netcdf in it since they're a little different
added netcdf and hdf5, fixed two minor bugs elsewhere
todo: implement pdb output and topology reading
pep8
index notation in mdconvert, fix  to two corner cases in readers
more stuff
shorter
printing
bugfix
refactor PDBFile into PDBTrajectoryFile
fix bug using topology
merge convert-script into master