fix: stringify error on 'Cannot convert a Symbol value to a string'

[Xesenix]

There were problems with using console.log while running test that resulted in errors like:

Chrome 66.0.3359 (Windows 7.0.0) moves should move rock box player up if they are adjacent one over each other FAILED
        TypeError: Cannot convert a Symbol value to a string
            at <Jasmine>
            at ContextKarma.stringify (http://localhost:9876/context.js:1804:34) // here stringify
            at ContextKarma.log (http://localhost:9876/context.js:1867:24)
            at <Jasmine>
            at Algorithm.resolveCell (src/game-00/main.test.ts:214654:13)
            at ordered.filter.obj (src/game-00/main.test.ts:214613:42)
            at <Jasmine>
            at Algorithm.update (src/game-00/main.test.ts:214613:23)
            at UserContext.it (src/game-00/main.test.ts:214494:19)

or

TypeError: Cannot convert a Symbol value to a string
        at ContextKarma.stringify (context.js:75:34) // here stringify
        at ContextKarma.log (context.js:138:24)
        at console.localConsole.(anonymous function) [as log] (context.js:242:16)
        at Context.<anonymous> (test.webpack.js:9:576885)

Related to issue: #2856

I have also noticed that i need to remove static/context.js and static/karma.js from .gitignore and include them in the repo so that this fix worked on my repository copy but didn't include it here as I am not sure they are built at some later point.

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[Xesenix]

I signed it!

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[johnjbarton]

Please change the first characters of your description to
fix(common):
Please add to your commit description
Fixes #2856
Please rebase and push again to trigger a retest.

[Xesenix]

@johnjbarton fixed issues test are passing tell me if you need anything more

[johnjbarton]

Thanks!