While development has slowed down over the past year, there's still been a number of features added to makechr. The release of 1.5 includes some fun new stuff:
* rgb-mapping
* A flag for choosing other ways to map RGB color spaces to that of the NES
* Arduboy support
* Some options to output graphical data for the Arduboy
* python3
* Support for python3
* decompose-sprites
* A new mode for processing composite sprites, using a much better algorithm than free-sprite-traversal
* arbitrary sized inputs
* Input images can be arbitrarily large, and as many nametables as needed will be used