Function name regex can get incorrect name for annoymous function

[bengourley]

Given the function source:

function () {
 // set the script that called this function
 updateLastScript(script)
 // immediately unset it
 _setTimeout(function () { updateLastScript(null) }, 0)
 cb.apply(this, arguments)
}

this Regex will incorrectly name the function updateLastScript which is an unfortunate sequence of a comment ending in function followed by a function call.

stack-generator/stack-generator.js

Line 30 in 1e295b6

if (/function(?:\s+([\w$]+))+\s*\(/.test(curr.toString())) {

a nested function definition can also trip it up:

function () {
 function jim() {
 // inner
 }
 more()
 statements()
}

The following update fixes these scenarios, correctly returning null for these two annonymous functions:

- if (/function(?:\s+([\w$]+))+\s*\(/.test(curr.toString())) { 
+ if (/^\s*function(?:\s+([\w$]+))+\s*\(/.test(curr.toString())) { 

I'm not sure if the "any preceding whitespace" part is strictly necessary but I don't think it hurts to permit that.

I can put together a PR for this including tests but I wanted to post it up as an issue before I get around to that while I work around it.