Version 67.0

Added
- Warning for packages not verified against repository index because missing hash

Changed
- Custom build system was replaced with autotools
- OpenSSL is now used to verify signatures instead of usign
- URI implementation no longer uses temporally files and passed instead everything
  in memory
- Download retries are removed, code now relies only on libcurl reconnection
- libb64 usage replaced with OpenSSL

Fixed
- Memory leak on archive open error
- Various compilation warning
- Invalid error complaining about path being called on on URI of invalid scheme