support for XHTML

<param name="scale" value="exactfit"> missed the "/" necessary for
ZeroClipboard to work with XHTML
fixed TypeError occurring in Chrome

"Uncaught TypeError: Cannot call method 'setSize' of undefined" was
caused by `document["global-zeroclipboard-flash-bridge"]` not working in
Chrome.
fixed support for IE

Removing the usage of `document["global-zeroclipboard-flash-bridge"]`
fixed the support of Chrome but unfortunately broke it for IE. This will
use both styles.
Merge branch 'master' into lhecker-master
cleaning up the pull request from @lhecker