Make SiteTree reference conditional

This makes the boilerplate code compatible for testing
framework-only sites.
Merge pull request #58 from oddnoc/safe-sitetree

Make SiteTree reference conditional in InitProcessor
API Support extended JS error reporting
Merge pull request #64 from tractorcow/pulls/stacktrace

API Support extended JS error reporting
Ensure that the window is maximised prior to running each step
Refactor default screen resize into SilverStripeContext
check a text is before or after another text
added comments for each step
check a text is before or after another text in an element
Merge pull request #60 from jeffreyguo/pulls/text-before-after

check a text is before or after another text
Merge pull request #67 from tractorcow/pulls/refactor-resize

Refactor default screen resize into SilverStripeContext
wait for DOM to remove attribute
use window.jQuery instead of $
Merge pull request #70 from jeffreyguo/pulls/jserror

wait for DOM to remove attribute
wait for DOM to remove attribute
use window.jQuery instead of $
updated to removeAttr method