px4io_uploader cleanup and minor optimization

Remove redundant code
Cleanup error handling in program function
Merge branch 'master' of https://github.com/PX4/Firmware
Forbid copy constructor in CDev
Enable stricter compile mode and ensure the most relevant bits are initialized. Needs more work to avoid the remaining warnings
Merge pull request #1187 from PX4/mavlink_strict

Mavlink strict
Merge pull request #1165 from jean-m-cyr/master

px4io_uploader cleanup and minor optimization
SYS_EXT_MAG parameter added for magnetometer selection
Hotfix: Allow the HMC5883 driver to continue to operate in auto mode
Merge branch 'master' into ext_mag_param
Implement the external mag param in a fashion that retains backward compatibility
Merge branch 'ext_mag_param' into logging
Add support for external sensors in startup
Strip excessive binary text to save some flash, start all three sensor sets
PCA8574: flash efficiency
RGBLED: flash efficiency