MIRTH-2954: Added static modifier to the start/stop connector methods.
Added methods to retrieve send date and response date from ImmutableConnectorMessage.
Issue: MIRTH-2956
Update commons-lang references to use commons-lang3 instead. Certain references to StringEscapeUtils.unescapeJavascript have not been updated yet. They are pending verification that the lang3 methods are equivalent.
Issue: MIRTH-2951
Update commons-lang StringEscapeUtils.unescapeJavascript references to use commons-lang3 StringEscapeUtils.unescapeEcmaScript instead. In both cases, they are functionally equivalent to their unescapeJava counterparts, so there shouldn't be any differences. Verified that map variables from scripts still show up correctly in the response settings dropdown and the various variable lists.
Issue: MIRTH-2951