Use clear options

[Sebmaster]

Since I just saw 546849f with the updated readme and options, we need to make sure the options have a clear purpose:

• path (legacyEvalPath): Will be defined in node.js environment (since it's needed anyways), but will default to null in browser environments. If the path is set, it will fall back to this file in case of a cross-site-origin restriction (i.e. IE10). It will therefore merge the meaning with the current ie10shim option.
• maxWorkers: Is obvious and will stay this way.
• synchronous: If webworkers are not available at all (i.e. IE < 10, etc), fall back to synchronous operations (with an initial setTimeout, currently no setTimeouts afterwards, they may be possible with .map() though).

Ping: @adambom - Please add the remaining options to the readme.

[Sebmaster]

I'm actually against the legacy prefix for the eval script. Yes it's used to deal with compatibility problems of IE, but it's also needed for require(script). I agree we might have to name it evalPath though.

[adambom]

I wasn't sure what to call it anyway. path just seemed a little ambiguous. I think evalPath makes sense.

[adambom]

I'll work this into the docs this evening.

[Sebmaster]

This should really be the last bug preventing us from switching master with rewrite.

[adambom]

Agreed. Digging into this now.