Activate LiquidTWI2 device detection and space-pad LCD status line.
Merge https://github.com/ErikZalm/Marlin into Marlin_v1
Prevent SD card insertion from causing a hang when using LiquidTWI2 device detection
Merge branch 'lcd_detected' of https://github.com/whosawhatsis/Marlin into Marlin_v1
Merge branch 'Marlin_v1' of https://github.com/ErikZalm/Marlin into Marlin_v1
Allow use of either SD Card slot when LCD Panel is configured.
Preference is for Controller SD slot before LCD Panel slot when both are occupied.
Merge branch 'Marlin_v1' of https://github.com/ErikZalm/Marlin into Marlin_v1
Merge branch 'Marlin_v1' of https://github.com/ErikZalm/Marlin into Marlin_v1
Merge branch 'Marlin_v1' of https://github.com/ErikZalm/Marlin into Marlin_v1
Support for Gen3 Monolithic electronics

Techzone Monotronics support, ignoring the tip manager and using fan connector as on Sprinter FW
TODO: Add support for tipmanager
Merge https://github.com/ErikZalm/Marlin into Marlin_v1
Merge branch 'Marlin_v1' of https://github.com/ErikZalm/Marlin into Marlin_v1
Merge branch 'Marlin_v1' of https://github.com/ErikZalm/Marlin into Marlin_v1
Merge branch 'Marlin_v1' of https://github.com/ErikZalm/Marlin into Marlin_v1
Add Arduino additions for Arduino 1.5.x.
Merge branch 'Marlin_v1' of https://github.com/ErikZalm/Marlin into Marlin_v1
Added gen7-dist - marlin now compiles for gen7
Merge branch 'Marlin_v1' of https://github.com/ErikZalm/Marlin into Marlin_v1
Change pinMode to SET_INPUT or SET_OUTPUT

Original code is using WRITE from fastio, but original used pinMode to
set pin direction and did not use the fastio SET_INPUT or SET_OUTPUT.
This caused an issue with the rotary encoder interface to  boards based
on teensyduino, since for teensyduino pin numbers for fastio and the
usual Arduino IO are different.
Real-time filament diameter measurement and control

This feature allows the printer to read the filament diameter
automatically and adjust the printer in real time.  Added code to read
an analog voltage that represents a filament diameter measurement.  This
measurement is delayed in a ring buffer to compensate for sensors that
are a distance away from the extruder.  The measurement is used to
adjust the volumetric_multiplier for the extruder.  Some additional g
codes (M404, M405, M406, M407) are used to set parameters and turn
on/off the control. g code M221 is updated.  Pins for RAMPS1.4, RAMBO,
and Printrboard are identified for analog input.  The configuration file
is updated with relevant user parameters.