_mocha: Allow boolean --reporter-options

[papandreou]

Previously "mocha --reporter-options foo" would blow up because an equal sign is required. This is quite unhandy for reporters that need to accept boolean (flag-ish) options.

This commit changes that so that a value-less reporter option will be interpreted as having a value of true.

This means that --reporter-options foo=bar,quux will turn into { foo: 'bar', quux: true }

[jbnicolai]

Am I correct in understanding that this is a non-breaking change?

Looks good :)

Edit: played with it a bit, clearly non-breaking. Thanks for the effort, @papandreou

[papandreou]

Yes, you are correct -- and thanks :)