v0.1.0

Release v0.1.0: first public release of libmantle.

What's new:
Everything, this is the first release. See the manual.
library: reasonably feature-complete implementation.
mantle-tool: end-to-end code generation.

Supports:
Austral 0.2.0
sel4cp verified non-MCS version

Note:
This was originally timed to coincide with the appearance of the ApSys
article and the verified seL4 Core Platform, but was advanced.