Make compatible with jQuery 1.10

Remove old test for jQuery 1.3.0 as plugin is now explicitly only compatible
with jQuery version 1.4.3 and higher anyway.
Prevent multiple instantiations of the plugin

Whitespace cleanup; PR37
Avoid load errors with document.namespaces in IE

Issue 64
Cache document, Math, undefined

Closure to cache document, Math, undefined -- should result in a very
slight performance improvement and smaller minified size.

(note that undefined doesn't need to be passed in as a parameter -- by
default any parameter not set will have the value of undefined)

PR 34
Release 2.1.2
Forgot to push the updated changelog