Changes for version 0.55
- Added support for many functions: plgradient, plstring, plstring3, plarc, plstransform, plslabelfunc, pllegend, plspal0, plspal1, plbtime, plconfigtime, plctime, pltimefmt, plsesc Removed deprecated functions: plarrows, c_plhls, c_plrgb, c_plrgb1 Fixed compiler warnings, did general clean-up.