Improved autotune instructions.
Added link to autotuning video.
Sanity check: Make sure it properly initializes

Previously the way the error code was dealt with meant if the
error code never changed from the initial value the alarm was
never initialized.  The alarm API already checks for toggling
the field so no need to avoid it in the wrapper method.
ManualControl: Ensure that alarm is always initialized

Same logic as the previous alarm.  It might make sense to move
the logic that prevents double toggling the fields into the
alarms.c file like AlarmSet.
ut logfs: allow flash layer to be destroyed after tests

This was leaking a small amount of memory for every test.

NOTE: This affects the unit test only.
ut logfs: free the fake flash sectors in the mock flash layer

This was causing a sector-sized memory leak for every
simulated sector erase.

NOTE: this affects the unit test only
Updated .gitignore file.
Merge pull request #225 from peabody124/sanity_check

Fix system alarm error codes
MPU6000: Stop driver when fifo overflows

The driver should _never_ lose sync since it cannot recover so
stop sending any data instead of phase shifted data.  There should
be code to recover the driver after this.
Fixed slight scaling error in LSM303DLHC accelerometer driver.

Also added units to the scaling parameters.
Added spaces around mathematical operators.
Merge pull request #237 from TauLabs/kenz/lsm303_scale_fix

Fixed slight scaling error in LSM303DLHC accelerometer driver.
Updated autotune instructions.
Merge pull request #229 from solidgoldbomb/fix-ut-memleaks

Fix unit test memory leaks
Update README.md

Replaced Above Ground Labs with Tau Labs.
Merge pull request #200 from TauLabs/kenz/autotune_instructions

Improved autotune instructions.
Merge pull request #219 from TauLabs/kenz/gitignore_update

Updated .gitignore file.
MPU6050: Stop driver when fifo overflows

The driver should _never_ lose sync since it cannot recover so
stop sending any data instead of phase shifted data.  There should
be code to recover the driver after this.
MPU60X0: Use a labeled PIOS_MPU60X0_INT_STATUS_OVERFLOW flag

Crytic unlabeled constants like 0x10 are bad.  Also there was a
flag that was defined but unused and also didn't match the
datasheet (PIOS_MPU60X0_INT_STATUS_FIFO_FULL) so I removed it.
Merge pull request #234 from peabody124/mpu6000_overflow

MPU6000: Stop driver when fifo overflows