Solc command line arguments

Solc now accepts multiple command line arguments.

- Most of the options concern the output of solc.
- Output to both a file and the standard output is possible.
- Unknown arguments are ignored
- Illegal values to arguments produce a legible error explaining to the user what he did wrong.
You mean when typing the arguments in the command line? If so I don't think we have any choice with the boost library. If I dig deeper I may find something. Not sure.

If it's for the help text I can add a dash in front of all of them to make them look like a list.