fix memory leak on thrown exception
remove unnecessary assignment
Merge pull request #39 from a0n/master

Added preinstall check for brew under mac os x
Merge branch 'master' of https://github.com/mscdex/node-gphoto2

* 'master' of https://github.com/mscdex/node-gphoto2:
  remove unnecessary assignment
  fix memory leak on thrown exception
Refactored C-style casts
bumped version