Restructure the locking around SPI transfers
Reduce excessive FMU stack usage
Update sensors tests
Merge pull request #1131 from PX4/pr-1131

Fix SPI struct unitialized use warning
A more compatible way of checking for an empty string.
Add quotes around the variable. It's safer.
Merge pull request #1154 from sjwilks/submodule_tool

Make the check for an empty string more compatible with linux distros
Merge pull request #1148 from PX4/fmu_stack

Reduce excessive FMU stack usage
Prevent stack overflow when flashing px4io

Large local variable causing stack overflow when attempting to flash
IO!!!
Read the full buffer

sizeof wont work here since file_buf is now a pointer
Merge pull request #1158 from jean-m-cyr/master

Prevent stack overflow when flashing px4io
Fixed the submodule check logic
mavlink: use all outputs in HIL mode
Merge pull request #1162 from PX4/hil_outs_fix

mavlink: use all outputs in HIL mode
Hotfix: Close fd before reusing it again
Merge branch 'master' of github.com:PX4/Firmware
Better Doxygen for topics, no code changes
GPS driver: Print velocity as part of status command
Merge pull request #1169 from PX4/comment-fixes

Better Doxygen for topics, no code changes
Add a check command and fix error reporting