doc: Update more docstrings to have one sentence summary as first line. Reviewed libinterp/corefcn directory. * libinterp/corefcn/__ilu__.cc, libinterp/corefcn/balance.cc, libinterp/corefcn/besselj.cc, libinterp/corefcn/betainc.cc, libinterp/corefcn/bitfcns.cc, libinterp/corefcn/bsxfun.cc, libinterp/corefcn/cellfun.cc, libinterp/corefcn/colloc.cc, libinterp/corefcn/conv2.cc, libinterp/corefcn/data.cc, libinterp/corefcn/debug.cc, libinterp/corefcn/defaults.cc, libinterp/corefcn/det.cc, libinterp/corefcn/dirfns.cc, libinterp/corefcn/dlmread.cc, libinterp/corefcn/dot.cc, libinterp/corefcn/eig.cc, libinterp/corefcn/error.cc, libinterp/corefcn/fft2.cc, libinterp/corefcn/fftn.cc, libinterp/corefcn/file-io.cc, libinterp/corefcn/filter.cc, libinterp/corefcn/find.cc, libinterp/corefcn/gammainc.cc, libinterp/corefcn/gcd.cc, libinterp/corefcn/getgrent.cc, libinterp/corefcn/getpwent.cc, libinterp/corefcn/getrusage.cc, libinterp/corefcn/graphics.cc, libinterp/corefcn/help.cc, libinterp/corefcn/hex2num.cc, libinterp/corefcn/input.cc, libinterp/corefcn/inv.cc, libinterp/corefcn/kron.cc, libinterp/corefcn/load-path.cc, libinterp/corefcn/load-save.cc, libinterp/corefcn/lookup.cc, libinterp/corefcn/ls-oct-ascii.cc, libinterp/corefcn/lsode.cc, libinterp/corefcn/lu.cc, libinterp/corefcn/luinc.cc, libinterp/corefcn/mappers.cc, libinterp/corefcn/matrix_type.cc, libinterp/corefcn/max.cc, libinterp/corefcn/md5sum.cc, libinterp/corefcn/mgorth.cc, libinterp/corefcn/nproc.cc, libinterp/corefcn/oct-hist.cc, libinterp/corefcn/ordschur.cc, libinterp/corefcn/pager.cc, libinterp/corefcn/pinv.cc, libinterp/corefcn/pr-output.cc, libinterp/corefcn/pt-jit.cc, libinterp/corefcn/quad.cc, libinterp/corefcn/quadcc.cc, libinterp/corefcn/qz.cc, libinterp/corefcn/rand.cc, libinterp/corefcn/rcond.cc, libinterp/corefcn/regexp.cc, libinterp/corefcn/schur.cc, libinterp/corefcn/sighandlers.cc, libinterp/corefcn/sparse.cc, libinterp/corefcn/spparms.cc, libinterp/corefcn/str2double.cc, libinterp/corefcn/strfind.cc, libinterp/corefcn/strfns.cc, libinterp/corefcn/sub2ind.cc, libinterp/corefcn/svd.cc, libinterp/corefcn/symtab.cc, libinterp/corefcn/syscalls.cc, libinterp/corefcn/sysdep.cc, libinterp/corefcn/time.cc, libinterp/corefcn/toplev.cc, libinterp/corefcn/tril.cc, libinterp/corefcn/tsearch.cc, libinterp/corefcn/typecast.cc, libinterp/corefcn/urlwrite.cc, libinterp/corefcn/utils.cc, libinterp/corefcn/variables.cc, scripts/polynomial/spline.m: Update more docstrings to have one sentence summary as first line.

--- a/libinterp/corefcn/dot.cc	Thu May 07 17:16:36 2015 -0400
+++ b/libinterp/corefcn/dot.cc	Sat May 09 17:19:30 2015 -0700
@@ -106,10 +106,13 @@
 DEFUN (dot, args, ,
        "-*- texinfo -*-\n\
 @deftypefn {Built-in Function} {} dot (@var{x}, @var{y}, @var{dim})\n\
-Compute the dot product of two vectors.  If @var{x} and @var{y}\n\
-are matrices, calculate the dot products along the first\n\
-non-singleton dimension.  If the optional argument @var{dim} is\n\
-given, calculate the dot products along this dimension.\n\
+Compute the dot product of two vectors.\n\
+\n\
+If @var{x} and @var{y} are matrices, calculate the dot products along the\n\
+first non-singleton dimension.\n\
+\n\
+If the optional argument @var{dim} is given, calculate the dot products\n\
+along this dimension.\n\
 \n\
 This is equivalent to\n\
 @code{sum (conj (@var{X}) .* @var{Y}, @var{dim})},\n\
@@ -281,11 +284,12 @@
 DEFUN (blkmm, args, ,
        "-*- texinfo -*-\n\
 @deftypefn {Built-in Function} {} blkmm (@var{A}, @var{B})\n\
-Compute products of matrix blocks.  The blocks are given as\n\
-2-dimensional subarrays of the arrays @var{A}, @var{B}.\n\
-The size of @var{A} must have the form @code{[m,k,@dots{}]} and\n\
-size of @var{B} must be @code{[k,n,@dots{}]}.  The result is\n\
-then of size @code{[m,n,@dots{}]} and is computed as follows:\n\
+Compute products of matrix blocks.\n\
+\n\
+The blocks are given as 2-dimensional subarrays of the arrays @var{A},\n\
+@var{B}.  The size of @var{A} must have the form @code{[m,k,@dots{}]} and\n\
+size of @var{B} must be @code{[k,n,@dots{}]}.  The result is then of size\n\
+@code{[m,n,@dots{}]} and is computed as follows:\n\
 \n\
 @example\n\
 @group\n\