Add "use strict;" to library

[arturnt]

We use a Google Closure compiler with EC5 strict mode. The library breaks at it's use of arguments.callee.

[ConradIrwin]

Unfortunately arguments.callee is the only way to get stack-traces on old versions of IE (< 10) :/.

It might be possible for us to compile a strict-mode compatible version of bugsnag.js; but if it's possible to exempt some files from the Closure compilers strict check, then that would be an easier solution.

[ConradIrwin]

(obviously, a strict mode compatible version would be incompatible with old IE, but that's a trade-off I think some people would be happy with).

[arturnt]

Is it possible to cut two versions (jQuery style)?

[ConradIrwin]

Almost certainly :). Can you tell me the easiest way to check a file against the Closure compiler's strict mode for testing?

[ConradIrwin]

Obviously for now, you're welcome to just delete the offending code in your fork (assuming you don't care about old IE).

[ConradIrwin]

Going to close this for now as it won't happen until we revisit how the library is built to support variants.