Improved support for panelolu2 encoder and buzzer

Heater wattage reporting for M105 using EXTRUDER_WATTS and BED_WATTS

- Remove the two version of 16mHz. Crystal and resonator use the same
fuse setting. Also, Arduino IDE only showed the first one 16Mhz as a
board option.

- Added 20Mhz board option.

Symptoms for incorrect fuse setting:
- X axis move in one direction
- limit switches fail to trigger
- unable to reprogram the device via bootloader
- stops working when the reset switch is pressed.
- device fails to bootup when power by a slow raise power supply.

Solution:
- Disabled the jtag
- set the correct clock selection bit
- set the correct bootloader memory size
- enable brown-out setting
- enable clock power up delay

I added #define for LCD_FEEDBACK_FREQUENCY_HZ and
LCD_FEEDBACK_FREQUENCY_DURATION_MS  which is used to alter the default
buzzer sound.

When selecting Panelolu2 in configuration.h:
- it automatically sets the correct ENCODER_PULSES_PER_STEP and
ENCODER_STEPS_PER_MENU_ITEM.
- if LCD_USE_I2C_BUZZER is defined it will also set the default
LCD_FEEDBACK_FREQUENCY_HZ and LCD_FEEDBACK_FREQUENCY_DURATION_MS

When selecting the sanguinololu 1284p the following is true:
- its now enables  LARGE_FLASH
- It enables the gcode M300 when the panelolu2 LCD_USE_I2C_BUZZER is
defined

Change diameter code to 'D'

Changed 1284p fuse setting for 8, 16 and 20 Mhz

Symtopns:

- X axis move in one direction
- limit switches fail to trigger
- unable to reprogram the device via bootloader
- stops working when the reset switch is pressed.
- device fails to bootup when power by a slow raise power supply.

Solution:
- Disabled the jtag
- set the correct clock selection bit
- set the correct bootloader memory size
- enable brown-out setting
- enable clock power up delay

For some reason that I can’t figure out, the decimal is dropped when
using ’S’ for the code.

Also some minor code improvements to M200.

Group hardware files for Arduino 1.x.x into hardware folder

M200 implementation

This is why I wanted to sleep on the code I wrote while falling asleep
rather than immediately submitting a pull request.

temperature.cpp: Actually use OVERSAMPLENR in the oversampling calculation.

Enable basic ULTRA_LCD screen w/o encoders and menus.

createTemperatureLookupMarlin.py: Add resolution comments and format for...

fastio.h: Add AT90USBxx_TEENSYPP_ASSIGNMENTS for teensyduino/Lincomatic/...

Makefile: Update for Arduino 1.0.5 and Teensyduino dependent boards (HAR...

createTemperatureLookupMarlin.py: Truncate to short after application of OVERSAMPLENR for improved resolution.

Format README.md with subsections

Having actual section headers instead of just bold text makes those parts of the document individually linkable.

Fix bugs in Extruder Runout Prevention, including DAMAGING HEAD CRASH

This seems to defeat the purpose of previous_millis_cmd, preventing the
time elapsed from previous_millis_cmd from ever reaching
max_inactive_time or stepper_inactive_time while the heat was on.

Fixes a bug in the Extruder Runout Prevention feature that caused the
extruder to move back to “current_position” after a move if it was
activated while the move was in progress. For long home moves (which
are longer than the dimensions of the machine’s working area), this
would cause the machine to crash into the far end of its travel after
homing. This usually occurred on the Z axis, which could result in
damage to the machine if you don’t hit the reset button in time.

Update ConfigurationStore.cpp

Unable to compile if ENABLE_AUTO_BED_LEVELING is not set (not set by default).

Makefile: Update for Arduino 1.0.5 and Teensyduino dependent boards (HARDWARE_MOTHERBOARD=={8,81,82,83,84})

Add Ultiboard2 electronics. With PWM current settings. For the few people that have this new board as experiment in their UM-Original.

Improvements to the auto bed leveling feature