Fix a regression in the emulated command bar - notably that each step in an "incremental" search is added to the search history (e.g. searching for "xyz" adds "x", "xy", and "xyz" to the search history). This involved creating a SearchParams struct to replace the individual m_lastSearchPattern, m_lastSearchCaseSensitive etc (probably worth doing in its own right) and re-instating the logic in EmulatedCommandBar that prevents the current search from being stored until it is executed (i.e. we press Enter, rather than cancelling it).

This highlights the problem of renaming ViRange -> Range - if we're doing "using KTextEditor;" and "using KateVi;", it's easy to create an ambiguity. Fix these ambiguities.