FakeVim: Select matched text when searching backwards

Task-number: QTCREATORBUG-7251
Change-Id: I3ef998683080b92e9e4a301434e45dc56c5a2f0a
Reviewed-by: hjk <hjk121@nokiamail.com>
FakeVim: Remove redundant variable

Change-Id: Ia10bd60de7e1a55903024f20bd041df23c85b151
Reviewed-by: hjk <hjk121@nokiamail.com>
FakeVim: Toggle boolean option and print option

Allow to use character '!' to toggle a boolean option and '?' to print
an option at the end of ":set {option}" command.

Change-Id: I7475c6a748c834c40de03cca57a59c428b1c4188
Reviewed-by: hjk <hjk121@nokiamail.com>