Also adds a addMatchesTo(SearchContext) which encapsulates this code and makes it safe to delete matches on object deletion, preventing possible memory leaks on SearchContext destruction.
Finally, don't copy all the SearchMatches already registered for each thread-local copy as that's just unused and unecessary overhead.
BIC, though SC.
svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=773473
* differentiate between resetSearchTerm and just setSearchTerm (to be used with the above)
* remove the SearchContext ptr from SearchMatch's dptr as it isn't used; don't want to mislead people or waste memory
* more const correctness
svn path=/trunk/KDE/kdebase/workspace/libs/plasma/; revision=764593
