bump version in CMakeLists.txt to 0.7 to make new release.

I noticed that I haven't managed this version number...

update README for v0.6 release.

add full UMP to MIDI1/SMF bytestream translator, with some breaking c…

…hanges.

- There are fixes in 64bit serialization regarding endianness.
- UMP to MIDI1 single translator is removed (internalized) and there is
  now `cmidi2_convert_ump_to_midi1()` which handles full translation and
  JR Timestamp to deltaTime converter (which leaves some TODOs though).

fix bank select calculation in cmidi2_convert_midi1_to_ump().

(and some cosmetic code comment)

update README. It's 1300 LoC, not tiny at all... Also bump version to…

… 0.3.4.

Add MIDI1 CC, RPN and META event constants.

it will be tagged as 0.3.2.

Add MIDI CI buffer generator functions with various tests (ongoing).

[actions] split doxygen/gh-pages (tag) from tests (push/PR).

bump version in Doxyfile.