ncurses 6.1 - patch 20181229

+ improve man/curs_mouse.3x with regard to xterm
+ modify tracemunch to accept filename parameters in addition to use
  as a pipe/filter.
+ minor optimization to reduce calls to _nc_reserve_pairs (prompted by
  discussion with Bryan Christ).
+ add test/pair_content.c and test/color_content.c
+ modify infocmp to omit filtering of "OTxx" names which are used for
  obsolete capabilities, when the output is sorted by long-names.
  Doing this helps when making a table of the short/long capability
  names.