#35 new attribute for spelling related errors

[Stephan Hennig]

To identify spelling related errors in XML output, attribute ruleID has to be checked against a number of possible values. The list of possible values may change in LanguageTool versions, which is a burden for external applications that parse LanguageTool's XML output. A dedicated attribute spelling="yes" would make life much easier for such applications, because they don't need to know details about LanguageTool internals.

[Daniel Naber]

This can now be done using the "locqualityissuetype" attribute.