dojox.math.BigInteger - replace references to navigator.appName with feature tests

[ben hockey]

dojox.math.BigInteger? has a couple of references to navigator.appName. given that this code (and code that uses this, specifically dojox.encoding.crypto.RSAkey) is likely to be useful outside of the browser, if possible, replacing references to navigator with feature detection is probably desirable.

[ben hockey]

fwiw, i took a look at ​http://www-cs-students.stanford.edu/~tjw/jsbn/ to get some insight as to the use cases for the different paths and it seems that its for performance reasons and is based on what seemed to work the fastest in particular browsers. testing which path is fastest for a particular browser might not be something to be feature tested but a check for if we're in the browser before referencing navigator should help. i'll work on a patch that guards the reference to navigator and defaults to the current else block for all cases other than the 2 specific ones tested for.

[Tom Trenka]

Reassigning to Eugene, who wrote the code.

[dylan]

Given that no one has shown interest in creating a patch in the past 4+ years, I'm closing this as patchwelcome.