v0.8.1

Release Notes

• Generate amast.tar.gz
• Improve API documentation
• Add am_timer_arm_ms()
• Rename am_event_get_pools_num() to am_event_get_npools()
• Add MIT license wording to docs/license.rst
• Rename HSM_HIERARCHY_DEPTH_MAX to AM_HSM_HIERARCHY_DEPTH_MAX
• Fix libs/hsm/tests/dtor.c
• Fix ms computation bug in libuv port of am_pal_time_get_ms()

From now on the amast source files are distributed in the form of amast.tar.gz.
The content of the tarball:

> tar -tzf amast.tar.gz
amast/amast.c
amast/amast_test.c
amast/amast_freertos.c
amast/amast_posix.c
amast/amast_cooperative.c
amast/amast_preemptive.c
amast/amast.h
amast/amast_test.h
amast/amast_libuv.c
amast/amast_config.h
amast/Makefile