Update .gitignore

Same .gitignore as in integration. Now ignores .doxyfile
Updated gitignore
Merge branch 'release1'
More accurate delay
Added updated arduino.h in new clean branch
Added PIO mappings in arduino.h
Renamed copypasted ifdefs in arduino.h for consistency
Accurate on 1 microsecond.
Fairly accurate

Decviates on 0-200 ns up to 10 microseconds.
Changed pwm_channel_disable() and made it block till the channel has
been disabled.
Small changes in PIO
Added pwm_set_clkx in pwm.c
Updated the test-file

Now contains accurate test function.
As accurate as it gets
Removed code that was commented away in delay.c
Bugfixed pwm_set_channel_frequency() in pwm.c
+ Created new function, pwm_init_peripheral(), and finished
pwm_init_channel() in pwm.c.
+ Made bugfix in pwm_turn_off_clkx().
+ Commented on the code.
Merge remote-tracking branch 'origin/integration' into pwm
Bugfix in pio_conf_pin_to_peripheral() in pio.c
Modified definition-names in pio.h