v0.7.0

1/ Python 2 is no longer supported.
2/ Some components are deprecated in favour of better replacements.
3/ Documentation build is much improved.
4/ Many smaller changes.

v0.5.0

1/ Rethought use of range, black level, and white level. Now almost every
component will assume 0..255 and if conversion to/from 16..235 is needed it
should be done as soon after input or before output as possible.