Merge pull request #3 from lqi/master

Add Pre-Compiled Header Support
Add option to exclude certain compiled files from json

To exclude certain compiled files from analyses, use parameter -e with a regex.
Update script description in argument parser.
Merge pull request #4 from pmnanez/patch-1

Add option to exclude certain compiled files from json
- optimized performance by not constructing the whole json compilation database in memory
- added support for logs coming from xctool's json-reporter
- refactored code using a tokenizer (shlex for -rare- complicated cases, a simple 'split' otherwise)
- made ObjectiveC implicit headers explicit
- made .pth recovery work also for .h source files
- moved top-level into main() for better style