Function added to set hypotenuse lengths for multi-axis steps.  These were previously computed on initialisation, but are now re-done after every M92.
Dud temperature count now has to reach 6 (about a second) before a heater trips out (Ian's request).  Also heater reset M code (M562) added.  Use that with great caution.
Bug where by selecting an already selected extruder did not reply (eg "ok" to Pronterface) fixed.
Default steps/mm set for new pulleys.
Build volume made less conservative (now 220x200x200).
Bug whereby heaters would not restart after an M0 is received fixed.
Added M27 response.
Homing modified to correspond with Ian's documentation...
Experimental macro/canned-cycle on the SD implemented.
Homeing after bed transform applied bug fixed in the duet branch.  The master branch will be updated after some further testing.  The problem was the X endstop.  If X is homed, that stop is triggered.  Homeing Y then only moves Y, and so only the Y endstop is tested.  But when the transform is applied X moves slightly when Y is homed (as it should) and the X endstop stoped the movement prematurely.  You will need to update the files on the SD card as well as the firmware to activate the fix.
All axis homing now done with canned cycle files.
Added more efficient canned cycle for when all three axes are being homed.
Synchronising duet branch with the mastr branch.
Workround added for bug in Pronterface (it sends 2 M24 commands on second file print).  M24 is now ignored if a file
is actively printing.
README updated to include compile instructions.
P parameter added to M559, so that macros can be uploaded.
Merge remote-tracking branch 'upstream/duet' into duet