Merge pull request #130 from NicolaAccettura/develop_sconsCleanUp

Develop scons clean up
Merge branch 'develop' of https://github.com/openwsn-berkeley/openwsn-fw into develop
Merge branch 'develop' of https://github.com/openwsn-berkeley/openwsn-fw into develop
Merge branch 'develop' of https://github.com/openwsn-berkeley/openwsn-fw into develop
FW-322. Fix.
Merge pull request #134 from NicolaAccettura/develop_FW-322

Develop fw 322