FlightMode: add rate, attitude, and virtual bar

These are explicit modes that will be used like Stabilized#,
but have the benefit of having a clear meaning for things
like GCS. Currently not implemented.
Flight: connect up new flight modes

These are the following hardcoded combinations of channel
settings:

 - RATE:       rate, rate, axis lock
 - ATTITUDE:   attitude, attitude, axis lock
 - VIRTUALBAR: virtualbar, virtualbar, axis lock

The custom modes STABILIZED{1,2,3} are still available like
previously.
MPU9250 9DOF sensor in SPI mode support
mpu9250: destroy sensor queues when allocation fails
mpu9250: fixed file headers
mpu9250: corrected code style and whitespaces according style guide
Flight: rename flight modes to acro and leveling

Previous commits introduced RATE and ATTITUDE as the name
for flight modes, but this creates ambiguity for the per-axis
settings versus the overall flight mode.

Now the modes are named ACRO and LEVELING, which is consistent
with some of the other software platforms out there. Again, the
original STABILIZED{1,2,3} are still available.
GCS Setup Wizard: use LEVELING and ACRO as default settings
Merge pull request #1191 from strnadda/pr_mpu9250_spi

MPU9250 9DOF sensor in SPI mode support
Merge pull request #1188 from peabody124/flight_modes

Flight modes
Battery Module config: fix current senser offset unit, allow larger offset (upto 200A)
misc_math: fix missing parenthesis for macro parameter
Merge pull request #1199 from kh4/next

Small fixes to battery module
Ground/Configinputwidget - small bug fix on 'for' statement
GCS/systemhealth added state estimation nohome html file
GCS/systemhealth added all state estimation files to the qrc file
GCS/systemhealth widget handle state estimation error on code
GCS/ConfigTaskWidget fixes bug on "if" statement
Merge pull request #1200 from guilhermito/bugfix

Two very small bugfixes
Merge pull request #1203 from guilhermito/systemhealth_fixes

Systemhealth fixes