Dom utils test coverage

This is an increase in the test coverage of the DomUtils methods. Most of them did not have unit tests, so I added several (nine tests).

I also fixed an issue in DomUtils that prevented certain branches of logic from being entered.

These are the tests I added:
testGetElementString -> Tests getElementString to ensure that the string form of an element is the same as what we expect. 

testGetElementByXpath -> Tests getElementByXpath to make sure that the elements are being retrieved properly (using Xpaths). 

testRemoveTags -> Tests removeTags to make sure that all tags are being properly removed from a Document.

testRemoveScriptTags -> Tests removeScriptTags to make sure that the script tags are being removed from a Document.

testGetDocumentToString -> Tests getDocumentToString to make sure that the Document is properly being represented as a string.

testGetTextValue -> Tests getTextValue to make sure that the text content is being retrieved. 

testRemoveNewLines -> Tests removeNewLines to make sure that new lines are being deleted.

testReplaceString -> Tests replaceString to make sure that substrings can be replaced properly using regular expressions.

testAddFolderSlashIfNeeded -> Test addFolderSlashIfNeeded to make sure that a / can be added to an incomplete path.