Added warnings and errors when sourceDocumentName is used

Output warning when a sourceDocumentName was given and output error when sourceDocumentName and sourceDocumentNames are given.
Merge remote-tracking branch 'upstream/master'
CodeNarc Report: UnnecessaryGString

Rule "UnnecessaryGString": The Strings can be wrapped in single quotes instead of double quotes.
Merge pull request #86 from McPringle/master

Added warnings and errors when sourceDocumentName is used