* Updated docs
* Re-factored vMPU drivers
* Non-backwards-compatible API change: uvisor_ctx is now called
__uvisor_ctx and requires the user to explicitly cast it to their own
private context structure.
This only affects applications with uVisor enabled.
* Use "public box" instead of main box for box 0.
- Enhanced Debug Box
- Allow hw-specific ACL extensions per region
- Reduce background region rights to debugger and core
- Added Beetle SoC uVisor support
- MPU code restructured