Plane: only call TECS when throttle is not suppressed

this helps prevent integrator buildup on the ground
HAL_AVR: corrected includes to replace #include "$HEADER" with #inlcude "utility/$HEADER"

adding -I for EVERY DIRECTORY isn't desirable

http://gcc.gnu.org/onlinedocs/cpp/Search-Path.html
Copter: added cast to remove compiler warning
HAL_AVR: reorder parameters to remove a warning with -Wreorder
AP_AHRS: make some more functions const
AP_HAL: resolved -Woverloaded-virtual warning

the function:
virtual size_t AP_HAL::Print::write(const uint8_t *buffer, size_t size);

was hidden in all derived classes by their
virtual size_t write(uint8_t) = 0; implementations.

To solve this, a non-virtual write(const uint8_t *, size_t) that calls a
virtual write_implementation was added.

This isn't necessary atm, because the derived classes don't call
write(const uint8_t *, size_t), BUT this decreases the apm2-quad Program
size by 40 bytes :D and removes warnings.
Filter: validity of array index was checked AFTER accessing the element.

(correction decreased Program size by 12 bytes)
extended .gitignore:
.directory (Dolphin's .DS_Store)
/.settings/ (eclipse)
AP_Compass: fixed rotations for COMPASS_ORIENT

this matches AHRS_ORIENTATION again
AP_Math: make the rotation numbers easier to find