FindAdv: Converting patterns without regex to use regex instead

FindAdv: Converting patterns without regex to use regex instead

Makes the code with less exceptions
  (no need to differentiate beteen use_regex and !use_regex)

Move the creation of regexes to own subroutine (Handles '#if QTSEARCH ... #endif')
Use cursor position differences instead of length of matched string. This is important for putSelectionAt()