Copy header files to system during 'make install' for convenience,
so that a developer can immediately compile code without having to
copy headers or reference this repo's copy of the header.
BeagleBone Black support. Credit goes to Purinda Gunasekara
for the code, reformatted to compile nicely into a shared
object like the others in this repo do.

https://bitbucket.org/purinda/rf24bb/src
Merge pull request #2 from mlsorensen/master

Copy header files to system during 'make install' for convenience,