Move supervisors to the examples folder.
Fix edoc for gpio:set_int/2.
restructure and clean Makefile
Merge pull request #6 from omerk/master

Fix Makefile, move supervisors and fix documentation for gpio:set_int/2
change erlang.mk include location
Merge pull request #7 from omerk/master

change erlang.mk include location in the Makefile
Add rebar support; pull in C dependencies
Fix path to gpio_port executable
Add alternative gpio_port implementation

Main change is to make it single threaded to
avoid random crashes on the BeagleBoneBlack.

Also:
  - Added support for getting rising vs.
    falling when registering for interrupts on
    both edges.
  - Allow reads on output pins so that you
    can see what they're currently set to.
  - Reduce prints; exit in more places when
    things go wrong.
Code cleanup
Comment out annoying io:format
Support oneway GPIO pins that are auto exported

This is needed to support GPIOs added by the gpio_helper
driver on the Beaglebone. These GPIOs come from a device
tree description so Linux automatically knows to export
them. The direction is specified in the dtb file, so it
can't be changed, and in fact, the direction file doesn't
even exist.
Fix erlcmd_dispatch size check bug
Refactor i2c support and Erlang command processing

This makes the gpio and i2c code both use the same Erlang command
processing routines. The I2C support has been modified to be process per
I2C endpoint since it is not common to want to mix code for two I2C
devices and this makes it harder to do that. It also makes the common
case of using one endpoint easier since you don't have to specify the
address all the time. Additionally, the code uses binaries instead of
lists and refers to buses by their integer number rather than a /dev
file reference.
Fix call to i2c read