HISTORY.txt - various updates over the last few months

This is far from comprehensive and people should feel free to further
expand it.
README.md update text

No need to start by focusing on the fork.  We have moved beyond that.
Doxygen: update the module documentation
More module documentation updates
Modules: delete unused magbaro module

Work on #556
Modules: delete unused MKSerial module

Work on #556
Modules: remove unused OsdEtStd module

Used to work for eagletree but the format was undocumented and this
broke.

Fixes #556
Libraries: doxygen header updates

Sorry a few line ending conversions slipped in too
UAVObjectTemplate: update documentation
Doxygen: clean up the outputs
Move coordinate conversion into the math library
pios_opahrs: remove old mainboard to ahrs comms code
Modules: more documentation cleanup
Delete CopterControl posix simulation.  Not used.

Work on #566
Flight targets: update documentation
GenericI2CSensor: documentation update
Bootloaders: documentation updates
More documentation cleanup
OSD: remove target, not in use or developemnt

Work on #566
STM32103CB_CC_Rev1: line ending conversion