Added helper functions making strings safe for jQuery selectors and enabling/disabling WET plugins and polyfills

1. Added helper function (jqEscape) for escaping strings to make them safe for jQuery selectors (to address issues with periods in id attributes)
2. Added helper function for enabling/disabling WET plugins and polyfills, including remembering a user's preference and offering a Basic HTML version/Standard version link

Note as part of this, a couple other plugins were affected because browser sniffing and page URL handling was more centralized and cached. Ideally a better alternative to browser sniffing would be found but in the interim it is used in a few cases.