The NearestNeighbour 2D resampling algorithm has been reshaped in order to offer the same interface as BiLinear. A typo in its name has been fixed. But NearestNeighbour does not work properly (bug not found yet)

A better way of submitting metadata to libpng has been implemented (ie: two vectors of strings that are then converted to char* to be given to libpng). The plugin basic options have been implemented, including size specifications. 

Some fonts improvements.