Don't double load jQuery

If jQuery is on the page and has the features debugkit needs, don't
download another copy. If jQuery is absent make a blocking XHR request
to fetch it and use eval LIKE A BOSS.
Fix up version number comparisons.
Tweak version comparision to allow for 1.10.x style version numbers.

Also widen the range of accepted versions.
Remove unused branch.
Merge pull request #97 from cakephp/no-double-jquery

Don't double load jQuery.

If the host page has jQuery with a compatible version loaded, don't load a second copy. Only when jQuery is missing, old, or super new will a second copy be loaded.