Handle only specific exceptions

- source_code.rb: During parsing, rescue only Racc::ParseError and
  RubyParser::SyntaxError
- config_file.rb: Raise ConfigFileException on invalid configuration
- application.rb: Rescue OptionParser::InvalidOption and ConfigFileException
  only

All other exceptions are not rescued and result in a full backtrace as generated
by Ruby itself.
Merge pull request #210 from troessner/no-general-exceptions

No general exceptions