Merge pull request #79 from jandrieu/master

Added error checking to make sure include paths actually exist
Postmerge
Prevent ReferenceError on Safari, fixes #80
Damn you CC, enough is enough. Let's get rid of this entirely. Fixes #80
Preparations to import structures, see #78
Replace imported file names with actual structures in proto2js/json, see #78
Imports before main based on build_json, see #78