Adds support for the timers module to browserify.

The public methods of the timers module are:

• setTimeout(callback, delay, [arg], [...])
• clearTimeout(timeoutId)
• setInterval(callback, delay, [arg], [...])
• clearInterval(intervalId)

and indeed, browsers support these already.

The timers module also includes some private methods used in other built-in Node.js modules:

• enroll(item, delay)
• unenroll(item)
• active(item)

These are used to efficiently support a large quantity of timers with the same timeouts by creating only a few timers under the covers.

Node.js also offers the immediate APIs, which aren't yet available cross-browser, so we polyfill those:

• setImmediate(callback, [arg], [...])
• clearImmediate(immediateId)

Linked lists are efficient when you have thousands (millions?) of timers with the same delay. Take a look at timers-browserify-full in this case.

MIT