USB fixes from Petteri Aimonen, cherry-picked.
Mark the ROMFS as const, saves ~25KiB of RAM.
Script name pointer array can be const. Fix a couple of lint errors while I'm here.
const the listener array, saves a little RAM.
Const a small array.
Moved filter states to stack RAM space
Move the bson sample data out of the BSS, saves 256 bytes of RAM
Hotfix: Throttle scaling in HIL
Merge branch 'master' of github.com:PX4/Firmware
Changes for multi-rate PWM output; default and alternate rates. ioctl protocol, PX4IO support.
Convert HIL and FMU drivers to the new multirate PWM interface.
Move PWM rate configuration, etc. into a separate utility and out of the individual drivers.
Moved trim for fixed wing to standard trim values, can now be calibrated via RC
Make communication rate between IO and FMU configurable
Fixed typo
Merge branch 'master' of github.com:PX4/Firmware into trim_calibration
IO board now disarms when FMU reboots when manual override is not an option
Attempt to fix sscanf() %n handling
Merge pull request #221 from PX4/const-sweep

Mark a number of things (most particularly the ROMFS) const to save RAM
Fix signs for fixed wing control, issue resulted from consistently flipped pitch response for IO and FMU