add closedir to simleshell commands that open directories
move digipot instance to CurrentControl module
make CurrentControl delete itself if not enabled
make Laser Module delete itself if not loaded
Merge pull request #100 from bgamari/fixes

Various things encountered during search for source of heap corruption
Gcode: simplify get_value with strtod
SimpleShell: use strtol to check for valid line limit instead of int(atof(...))
Switch gcc4mbed.c license to Apache v2

I never meant for this to have a LGPL license on it.  I must have
copied that from MRI code base at some point.  I should have been
Apache v2.
Fixes issue #101

Simplified naming convention of sample config file and re-organized into
directory structure where more than one sample can live with each sample having
the correct final name of "config".

I have included a sample README.TXT file in the ConfigSamples directory that
others more knowledgable about this area may want to update.
Merge pull request #96 from wolfmanjm/upstreamedge

add closedir to simpleshell commands that open directories
Merge pull request #92 from wolfmanjm/move_digipot

move digipot to CurrentCOntrol Module
Player: Reduce block queue depth to 16

It seems we don't have enough memory to keep this many blocks around;
the heap collides with the stack on LPC1769.