Changed EOF detection in qw_edit_paint().

It now tries a qw_blk_move() further the block size and, if it
fails, it's assumed it's at the end of the text and a EOF blank
space is added.
Fixed a buffer size calculation bug in qw_edit_paint().
Do not show EOL markers by default.
Added matching paren colorization.
Fixed bug in color_match_p() calling arguments.
New files qw_sh.h and qw_sh.c.
Added a pointer to a qw_sh_t inside qw_edit.
New function qw_sh_apply().
Fixed apply_token() to really test tokens.
Got rid of tok_cmp().