Consider parsing stack strings instead of using Error.prepareStackTrace

[domenic]

Currently accessing an error's stack at all---even to log it---makes it unsuitable for Q's rewriter, since it is reified and thus Error.prepareStackTrace is never called.

If we manipulated and parsed the strings directly, instead of using Error.prepareStackTrace to grab and format the stack frames, this hazard would be avoided. Additionally, we would then work in Internet Explorer 10, since they have adopted the V8 stack trace format.

[kriskowal]

@domenic I’ll leave it to you to decide whether to merge #121.

[domenic]

#121 is probably worth merging as a stopgap before I do more extensive stack trace-related work, but I need to get Q.onerror working first as a revision of #94. Will work on it tonight.