Merge pull request #45 from neriberto/master

Added more 1688 signatures to userdb.txt
Add libpe as a submodule now that it's an independent repository.
Merge pull request #46 from jweyrich/master

Add libpe as a submodule now that it's an independent repository.
- Allow to use other compiler using CC env var
Merge pull request #48 from felipensp/clang_build

- Allow to use other compiler using CC env var