My PID_INTEGRAL_DRIVE_MAX was at 96, which was insufficient for my bed
to reach its intended temperature. The head requires a low maximum power since
I run on 24 volts and it has a somewhat low thermal mass.
It would seem that the pattern matches do not work when the source
file is created when make is running. The result of this is that it is
necessary to run "make" twice to build the firmware.
This adds an explicit rule without a pattern match for building
applet/Marlin.cpp it corrects the make behaviour at the cost of adding
a little redundancy in the Makefile.
Jonathan Bastien-Filiatrault