Implementing StringStream.
Added multipwm test
Merge branch 'master' of https://github.com/astralien3000/aversive-- into multipwm
Created MultiPWM system (common algo)
Multipwm example now compiles.
Test needed !
Merge remote-tracking branch 'origin/master' into stringstream
Adding a test for StringStream.
Merge pull request #54 from astralien3000/stringstream

StringStream
MultiPWM test is OK
Added arduino pinmap in comments (multipwm test).
Merge branch 'master' of https://github.com/astralien3000/aversive-- into multipwm
Adding missing license headers in MultiPWM header files. Adding a static_assert in the MultiPWM header files for the yet unsupported platforms. Some other minor things regarding coding conventions.
Changing the _byte attribute in BoolRef from `u8*` to `u8&`. Updating Array and Pair boolean specialisation in consequences as well as BoolRef's test.
Merge pull request #59 from astralien3000/boolref

BoolRef's _byte attribute changed from pointer to reference
Merge pull request #56 from astralien3000/multipwm

Multipwm
Merge branch 'master' of https://github.com/astralien3000/aversive-- into pin_api
Modified Pin Devices into DigitalPin, as said in the issue #21.
Completed the DigitalPin API with toggle, isInput, isOutput