doc: Update more docstrings to have one sentence summary as first line. Reviewed build-aux, libinterp/dldfcn, libinterp/octave-value, libinterp/parse-tree directories. * build-aux/mk-opts.pl, libinterp/dldfcn/__magick_read__.cc, libinterp/dldfcn/amd.cc, libinterp/dldfcn/audiodevinfo.cc, libinterp/dldfcn/audioread.cc, libinterp/dldfcn/ccolamd.cc, libinterp/dldfcn/chol.cc, libinterp/dldfcn/colamd.cc, libinterp/dldfcn/convhulln.cc, libinterp/dldfcn/dmperm.cc, libinterp/dldfcn/fftw.cc, libinterp/dldfcn/qr.cc, libinterp/dldfcn/symbfact.cc, libinterp/dldfcn/symrcm.cc, libinterp/octave-value/ov-base.cc, libinterp/octave-value/ov-bool-mat.cc, libinterp/octave-value/ov-cell.cc, libinterp/octave-value/ov-class.cc, libinterp/octave-value/ov-fcn-handle.cc, libinterp/octave-value/ov-fcn-inline.cc, libinterp/octave-value/ov-java.cc, libinterp/octave-value/ov-null-mat.cc, libinterp/octave-value/ov-oncleanup.cc, libinterp/octave-value/ov-range.cc, libinterp/octave-value/ov-struct.cc, libinterp/octave-value/ov-typeinfo.cc, libinterp/octave-value/ov-usr-fcn.cc, libinterp/octave-value/ov.cc, libinterp/parse-tree/lex.ll, libinterp/parse-tree/oct-parse.in.yy, libinterp/parse-tree/pt-binop.cc, libinterp/parse-tree/pt-eval.cc, libinterp/parse-tree/pt-mat.cc: doc: Update more docstrings to have one sentence summary as first line.

--- a/libinterp/dldfcn/convhulln.cc	Sun May 03 17:00:11 2015 -0700
+++ b/libinterp/dldfcn/convhulln.cc	Sun May 03 21:52:42 2015 -0700
@@ -77,8 +77,11 @@
 @deftypefn  {Loadable Function} {@var{h} =} convhulln (@var{pts})\n\
 @deftypefnx {Loadable Function} {@var{h} =} convhulln (@var{pts}, @var{options})\n\
 @deftypefnx {Loadable Function} {[@var{h}, @var{v}] =} convhulln (@dots{})\n\
-Compute the convex hull of the set of points @var{pts} which is a matrix\n\
-of size [n, dim] containing n points in a space of dimension dim.\n\
+Compute the convex hull of the set of points @var{pts}.\n\
+\n\
+@var{pts} is a matrix of size [n, dim] containing n points in a space of\n\
+dimension dim.\n\
+\n\
 The hull @var{h} is an index vector into the set of points and specifies\n\
 which points form the enclosing hull.\n\
 \n\