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.
Improvements and bug fixes in sensor delay buffer for filament sensor code

Improvement to avoid reinitializing delay buffer with every print. Fixed
issues in buffer indexing and memory out of bounds due to floating point
imprecision.  Simplified the code by avoiding conversion to standard
diameter and 1cu mm extrusion, which caused complications in determining
mm extruded.
Filament sensor changes to config file

Update the config file for improvements and clarifying what diameter to
use in the slicer software.
Revert "Change pinMode to SET_INPUT or SET_OUTPUT"

This reverts commit 1d0fe035f3aeb4af0e686fcb13c9a720248db462.
Correct analog sampling time for additional A to D sample

Adjusted the  #define PID_dT to reflect 10 A to D sample steps, vs
original 8.
Update README.md

Added the new m-codes to this document.
Fixed typo.

Signed-off-by: Christian Inci <chris.pcguy.inci@gmail.com>
Merge pull request #1037 from filipmu/Filament-Sensor

Support for a filament diameter sensor
Merge pull request #1104 from ch100/Marlin_v1

Fixed typo.
Updated example configurations for Delta printers
Merge pull request #1133 from monkeydave/update_delta_config

Updated example configurations for Delta printers
Merge pull request #2 from ErikZalm/Marlin_v1

Sync up to Marlin
Commented out FILAMENT_SENSOR #define

Commented out the FILAMENT_SENSOR define so that it is not enabled by
default.  Code does not work on all hardware variants.
Merge pull request #1138 from filipmu/Marlin_v1

Comment out the FILAMENT_SENSOR define by default in config.
Adaption of LCD info screen

Here comes a compile-time operation to match the extruder symbols on the
info screen to the set number of extruders in configuration.h.
When only one extruder is selected, the "1" on the symbol will not be
displayed.
Merge pull request #1143 from Silly105/Marlin_v1

Changed graphic LCD info screen to match the set # of extruders
Add Travis CI config to build Marlin firmware.
Merge pull request #1148 from krasin/travis

Add Travis CI config to build Marlin firmware.
M0-M1 Enhancements

Allow M0 and M1 to include a message string. Ignore clicks on “Wait for
user” so that the Info Screen stays up.