Added respond_to_missing? implementation to ThinkingSphinx::Search, so
it correctly says that it responds to methods delegated to masks.
Merge branch 'develop' into develop_respond_to

Conflicts:
	spec/thinking_sphinx/search_spec.rb
Added  basic unit  test and  proper 'method'  call handling  for methods
delegated to masks / context.
Slight formatting tweak to @bkon's helpful contribution.