Command line arguments parser

[agalbachicar]

Based on PR #39, a custom CLI parser has been introduced. If that code remains, it would be great to use a dedicated library instead of the custom parser. As Drake already uses gflags, it is a great candidate.

[liangfok]

Somewhat related to this ticket: it would be nice if the CLI parser supported --help. It currently errors out:

$ ./install/delphyne-gui/bin/visualizer --help
[Msg] Visualizer 0.1.0
[Err] [global_attributes.cc:48] The argument: "--help" does not contain "="
terminate called after throwing an instance of 'std::runtime_error'
  what():  The argument: "--help" does not contain "="

Aborted (core dumped)