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/fftw.cc	Sun May 03 17:00:11 2015 -0700
+++ b/libinterp/dldfcn/fftw.cc	Sun May 03 21:52:42 2015 -0700
@@ -43,12 +43,14 @@
 @deftypefnx {Loadable Function} {} fftw (\"threads\", @var{nthreads})\n\
 @deftypefnx {Loadable Function} {@var{nthreads} =} fftw (\"threads\")\n\
 \n\
-Manage @sc{fftw} wisdom data.  Wisdom data can be used to significantly\n\
-accelerate the calculation of the FFTs, but implies an initial cost\n\
-in its calculation.  When the @sc{fftw} libraries are initialized, they read\n\
-a system wide wisdom file (typically in @file{/etc/fftw/wisdom}), allowing\n\
-wisdom to be shared between applications other than Octave.  Alternatively,\n\
-the @code{fftw} function can be used to import wisdom.  For example,\n\
+Manage @sc{fftw} wisdom data.\n\
+\n\
+Wisdom data can be used to significantly accelerate the calculation of the\n\
+FFTs, but implies an initial cost in its calculation.  When the @sc{fftw}\n\
+libraries are initialized, they read a system wide wisdom file (typically in\n\
+@file{/etc/fftw/wisdom}), allowing wisdom to be shared between applications\n\
+other than Octave.  Alternatively, the @code{fftw} function can be used to\n\
+import wisdom.  For example,\n\
 \n\
 @example\n\
 @var{wisdom} = fftw (\"dwisdom\")\n\