doc: Update more docstrings to have one sentence summary as first line. Reviewed specfun, special-matrix, testfun, and time script directories. * scripts/specfun/expint.m, scripts/specfun/isprime.m, scripts/specfun/legendre.m, scripts/specfun/primes.m, scripts/specfun/reallog.m, scripts/specfun/realsqrt.m, scripts/special-matrix/gallery.m, scripts/special-matrix/hadamard.m, scripts/special-matrix/hankel.m, scripts/special-matrix/hilb.m, scripts/special-matrix/invhilb.m, scripts/special-matrix/magic.m, scripts/special-matrix/pascal.m, scripts/special-matrix/rosser.m, scripts/special-matrix/toeplitz.m, scripts/special-matrix/vander.m, scripts/special-matrix/wilkinson.m, scripts/testfun/assert.m, scripts/testfun/demo.m, scripts/testfun/example.m, scripts/testfun/fail.m, scripts/testfun/rundemos.m, scripts/testfun/runtests.m, scripts/testfun/speed.m, scripts/time/asctime.m, scripts/time/calendar.m, scripts/time/clock.m, scripts/time/ctime.m, scripts/time/datenum.m, scripts/time/datestr.m, scripts/time/datevec.m, scripts/time/etime.m, scripts/time/is_leap_year.m, scripts/time/now.m, scripts/time/weekday.m: Update more docstrings to have one sentence summary as first line.

--- a/scripts/special-matrix/hadamard.m	Sun May 03 15:36:23 2015 -0700
+++ b/scripts/special-matrix/hadamard.m	Sun May 03 17:00:11 2015 -0700
@@ -21,10 +21,11 @@
 
 ## -*- texinfo -*-
 ## @deftypefn {Function File} {} hadamard (@var{n})
-## Construct a Hadamard matrix (@nospell{Hn}) of size @var{n}-by-@var{n}.  The
-## size @var{n} must be of the form @math{2^k * p} in which
-## p is one of 1, 12, 20 or 28.  The returned matrix is normalized,
-## meaning @w{@code{Hn(:,1) == 1}} and @w{@code{Hn(1,:) == 1}}.
+## Construct a Hadamard matrix (@nospell{Hn}) of size @var{n}-by-@var{n}.
+##
+## The size @var{n} must be of the form @math{2^k * p} in which p is one of
+## 1, 12, 20 or 28.  The returned matrix is normalized, meaning
+## @w{@code{Hn(:,1) == 1}} and @w{@code{Hn(1,:) == 1}}.
 ##
 ## Some of the properties of Hadamard matrices are:
 ##