Code quality: Do not rescue Exception in worker.

Should never rescue Exception; not really sure how this crept in! See the top
answer in [1] for why not to do this. In this case though we *do* want to catch
almost everything so we grab StandardError by default.

[1]http://stackoverflow.com/questions/10048173/why-is-it-bad-style-to-rescue-exception-e-in-ruby
[TAV-460] Fix embedded run refresh.

Need to pull in host application's javascript manifest instead of just Taverna
Player's.
Use a simplified doctype for the embedded layout.

Matches the dummy application's default layout and should be overridden by the
host application anyway.
Code quality: Do not use instance variables in partials.

This hides the real requirements of the partial. Using locals makes this
explicit and auto-documents the requirements.
Code quality: Use the simplified form of "render".