support for strict mode

[tmont]

Support for passing along the --use_strict flag from mocha to _mocha. Also fixes a strict code incompatibility with the undeclared variable Reporter in _mocha, as outlined in #1879.

Tests all pass and the lib works on node v4.2.3 and v5.1.1.

[danielstjules]

Could you add it to https://github.com/mochajs/mocha/blob/master/bin/_mocha#L58 Without that, it's not usable via mocha.opts

[tmont]

done, and i rebased as well.

[boneskull]

this needs a minor or major release. I realize now my chalk-related changes need a major. I can back them out and put them in v3 branch so we can stick this in v2.4.0

[danielstjules]

Minor makes sense, but this change wouldn't force a major, right?

[boneskull]

Nope just an pption

[danielstjules]

Thanks again!

[h2jorm]

Some code in mkdirp module can not be executed in strict mode. So '--use_strict' flag is still not accessable.

leeching:s-cms leeching$ npm tst

> s-cms@0.0.1 test /Users/leeching/coding.net/s-cms
> mocha --harmony --harmony-destructuring --use_strict test

/Users/leeching/coding.net/s-cms/node_modules/mkdirp/index.js:19
        mode = 0777 & (~process.umask());
               ^^^^

SyntaxError: Octal literals are not allowed in strict mode.
    at exports.runInThisContext (vm.js:53:16)
    at Module._compile (module.js:374:25)
    at Object.Module._extensions..js (module.js:405:10)
    at Module.load (module.js:344:32)
    at Function.Module._load (module.js:301:12)
    at Module.require (module.js:354:17)
    at require (internal/module.js:12:17)
    at Object.<anonymous> (/Users/leeching/coding.net/s-cms/node_modules/mocha/lib/reporters/xunit.js:10:14)
    at Module._compile (module.js:398:26)
    at Object.Module._extensions..js (module.js:405:10)
npm ERR! Test failed.  See above for more details.

[danielstjules]

Ah, I should have tested it again after the rebase. The issue is a result of merging #1995

Edit: Looks like mkdirp 0.5.1 fixes this :)

[danielstjules]

Fixed in master. Thanks!