Add tests for around using source from options, falling back to source element in the document
Add test for sourceUrl support (currently failing due to no implementation)
Add support for sourceUrl (fixes previous tests)
Add tests for both linux and window newlines to ensure same behaviour

Not sure why this only seems to affect sourceUrl and not embedded
textarea? :/
Merge pull request #108 from DanTup/master

Add support for sourceUrl in options; to allow pulling slide content from a separate file