When interrupts are cancelled on any interruptable class, the resource is now
freed. Previously, the resource was only freed if the object is destructed
before CancelInterrupts() is called, so it was impossible to create and
destruct more than 8 interrupts.
The interrupts resource object is now in InterruptableSensorBase instead of
SensorBase.
A synchronous interrupt integration test was added.
Change-Id: I0806176340cecd4c1480dd8f043474cc05919f24
Made a toplevel directory for C++ and C++ tests
Change-Id: I4bc2074a7036ec7fe79568b411637a5bee9eb5b3
Added the C++ testing framework and one test
Change-Id: I1e80a1e16b251a49666820a9d4c8caa025da9785
