The PSRFITS definition has been changed to v2.8, and with it a number of new keywords have been created in the PHU -- RA, DEC, DATE_OBS etc
This commit includes changes to PSRFits::writePHU() to write these keywords and removing the respective commands from PSRFits::addNewKeywords(). Note that OBSFREQ has not been added yet to the definition.
A new function Block::getCoordMode replaces the old getEquinox, which changes to output just the equinox in the case of equatorial coordinates.
Otherwise, minor fixes, mostly removing dead code.