models: no longer call beginResetModel()/endResetModel()

Rather remove every row and then insert every new row when resetting the
whole model.
Rationale: QItemSelectionModel do not send selectionChanged() signal
when the model is reset, therefore views (or any other connected object)
are not notified that selection has changed, whereas they are when
removing rows containing selected items.
paramset: fixed evaluation of % when used as an escape character

When encountered before a character not recognized as evaluatable (i.e.
neither { nor ! nor _ nor an ASCII-7 letter) % must be used as an escape
character, that is, leave next character unevaluated, this is usefull to
escape % using %%

raw sequence  old (buggy) evaluation  fixed evaluation
%%            %%                      %
%=            %=                      %
%20           %20                     20