Small changes on the LCD panel, let the speed control work better, line up the parameter edit the same as the menu, remove some unused defines, and remove the Z from the 10mm move menu.

Automatically set *_MIN_PIN and *_MAX_PIN according to *_HOME_DIR.

fixed  (#328) pwm generation at pin D12 and D13

For boards with only one endstop per axis, automatically set *_MIN_PIN and *_MAX_PIN according to *_HOME_DIR.

fixed pwm generation at pin D12 and D13 when one of them is used as FAN_PIN on Sanguino, added soft pwm entry for FAN_PIN in temperature.cpp

Fix the russian translation.

Reverted the patch by KevinOConnor, as it crashes some versions of avr-gcc and caused linking issues.

Add additional optimization flags to Makefile

Use "whole program" and "link time optimization" features of gcc.  The
whole-program optimization enables the compiler to evaluate the entire
firmware for optimization instead of just one code file at a time.
This leads to better overall optimizations.

The "relax" option enables the linker to convert certain "call"
instructions to the smaller "rcall" instruction.  This reduces the
size of the resulting binary.

The big LCD code update. This splits the display and menu implementation. Paving the way for future different displays. It also makes it easier to modify the menu structures while keeping everything consistant. Note that this most likely breaks the translations, which need to be updated.

Add PID functional range setting. With high powered heaters the current functional range of 10 degrees causes high overshoots as the PID needs to kick in before the temperature hits 10 degrees below target.

Fix the sensitive pin definitions, there where analogue numbers in the digital pin list. Also made M42 without a P function on the LED_PIN (which was otherwise a useless pin definition)

Fix endstop pins for Printrboard

Added some missing Mxxx comments to M commands. Fixed the unsetting of the timer dividers for the fast PWM fan.