Project name support '-' and '_'

[tsaikd]

Any reason to disable '-' and '_' for project name?

[aanand]

Yes - we keep track of services and what containers are running in them by naming containers <project>_<service>_<number> (in the absence of any other way of storing metadata on containers), so allowing underscores in the project name will confuse that.

As for hyphens, it's mostly an aesthetic thing - mixing hyphens and underscores is a bit icky.

[bfirsh]

Plus we want to switch to using them as the separator: #229

@tsaikd I'm afraid this time again we can't accept your contribution. Thanks for the help though!

[ghost]

This is not a reason to disable dashes!