Mavsdk

Release with a couple of bugfixes, comment improvements, and many additions in the gRPC backend.
This is essentially a test release before 1.0.0.

- Support for `note` and `warning` doc tags (374)
- Serial connection support for Windows (375)
- gRPC backend additions and fixes (376, 377, 382, 385, 397, 405, 407, 409, 416)
- Various build fixes (378, 379, 383 386, 413)
- Various bugfixes (384, 387, 390, 391, 393, 402, 406)
- Removed deprecated `armeabi` Android build (392)
- Improved public comments (394, 415)
- Fixes in examples (395, 400, 403, )
- Added thread pool for user callbacks (396)
- Switch from astyle to clang format (410)
- Sync mode setter for camera (414)

Release after a big round of refactoring and improvements:

- Serial connection support on macOS (372)
- gRPC backend (371, 369, 357, 352, 342, 330, 327, 320, 313, 303, 300, 299, 295, 266)
- gRPC proto defined (346, 302)
- Build system fixes (370, 354, 283, 276)
- Notification of already connected system on discover (360)
- YouCompleteMe config (356)
- Camera actions and settings added (338)
- Support for gimbal ROI (323)
- Multi-component handling (310)
- Docs fixes (298, 297, 271, 246, 242, 237, 223)
- New examples for follow me and importing a QGC mission (274)
- Ability to import QGC mission plans (235)
- Support to connect based on a URL argument (264)
- Initial CI work for Jenkins (257)
- Follow me plugin improvements and example (217, 199)
- Various fixes (349, 324, 316, 311, 308, 306, 289, 288, 280, 230, 228, 206, 203)

Release before a round of big refactorings.

Changes:
- Offboard example added (116)
- Added fields to info (118)
- Mavlink statustexts added for debugging (119)
- Fixed RC status bug (123)
- Gimbal plugin added (124)
- Support for .deb and .rpm packages (130, 196, 198)
- Add support for delays before camera actions (131)
- Simplify offboard usage (134)
- Follow me plugin added (142, 199)
- gRPC work (143, 174, 175)
- Support to download mission (145)
- Use fake time for unit tests (147)
- VTOL transition support (150, 163)
- Fix 100% CPU bug for serial connections (177)

- Added `dronecore::is_connected()` interface 97
- Improved takeoff and land integration tests and examples 98
- Improved mission example 102, 104
- CI, release build improvements, code coverage 105, 113
- Fallback to mavlink system ID if UUID is not available 109
- CI integration tests prototype 110
- Various fixes 108, 111, 115, 114
- Prototype of gRPC server and Python client 48

Static C++ library for MAVLink