Automatically instantiate page objects in step libraries

Any uninstantiated PageObject fields in step libraries will now be automatically instantiated.
Minor refactoring
Updated version number and fixed a bug that caused tests to wait unnecessarily in subsequent steps after a step had failed
Don't use the File system based requirements provider if other custom providers are specified
Refined the requirements reporting
Merge branch 'master' of github.com:thucydides-webtests/thucydides