Release v4.0.1

Changelog:

- Port from autotools to CMake build system
- Arbitrary color palette configurable via API
- More unit tests
- Release tag name changes from libtsm-x.y.z to vx.y.z
- Bug fixes

API changes:

- tsm_screen_draw_cb now takes an uint64_t as id

This is the first libtsm release as a stand-alone library. We skipped…

… version 2

to avoid incompatibilities with the kmscon-builtin libtsm. Please see the
release announcement for a list of changes and new features.