doc: Update more docstrings to have one sentence summary as first line. Reviewed optimization, polynomial, signal script directories. * scripts/optimization/fminbnd.m, scripts/optimization/fminsearch.m, scripts/optimization/fminunc.m, scripts/optimization/fsolve.m, scripts/optimization/fzero.m, scripts/optimization/glpk.m, scripts/optimization/lsqnonneg.m, scripts/optimization/pqpnonneg.m, scripts/optimization/qp.m, scripts/optimization/sqp.m, scripts/polynomial/compan.m, scripts/polynomial/mkpp.m, scripts/polynomial/mpoles.m, scripts/polynomial/pchip.m, scripts/polynomial/poly.m, scripts/polynomial/polyaffine.m, scripts/polynomial/polyder.m, scripts/polynomial/polyeig.m, scripts/polynomial/polyfit.m, scripts/polynomial/polygcd.m, scripts/polynomial/polyint.m, scripts/polynomial/polyout.m, scripts/polynomial/polyval.m, scripts/polynomial/ppder.m, scripts/polynomial/ppint.m, scripts/polynomial/ppjumps.m, scripts/polynomial/ppval.m, scripts/polynomial/residue.m, scripts/polynomial/roots.m, scripts/polynomial/spline.m, scripts/polynomial/splinefit.m, scripts/polynomial/unmkpp.m, scripts/signal/arch_fit.m, scripts/signal/arch_rnd.m, scripts/signal/arma_rnd.m, scripts/signal/autoreg_matrix.m, scripts/signal/bartlett.m, scripts/signal/blackman.m, scripts/signal/detrend.m, scripts/signal/diffpara.m, scripts/signal/durbinlevinson.m, scripts/signal/fftconv.m, scripts/signal/fftfilt.m, scripts/signal/fftshift.m, scripts/signal/filter2.m, scripts/signal/freqz.m, scripts/signal/hamming.m, scripts/signal/hanning.m, scripts/signal/hurst.m, scripts/signal/ifftshift.m, scripts/signal/periodogram.m, scripts/signal/sinc.m, scripts/signal/sinetone.m, scripts/signal/sinewave.m, scripts/signal/spectral_adf.m, scripts/signal/spectral_xdf.m, scripts/signal/spencer.m, scripts/signal/stft.m, scripts/signal/synthesis.m, scripts/signal/unwrap.m, scripts/signal/yulewalker.m: Update more docstrings to have one sentence summary as first line.

--- a/scripts/polynomial/polyout.m	Mon May 04 14:22:02 2015 -0700
+++ b/scripts/polynomial/polyout.m	Mon May 04 21:50:57 2015 -0700
@@ -20,7 +20,9 @@
 ## @deftypefn  {Function File} {} polyout (@var{c})
 ## @deftypefnx {Function File} {} polyout (@var{c}, @var{x})
 ## @deftypefnx {Function File} {@var{str} =} polyout (@dots{})
-## Write formatted polynomial
+## Display a formatted version of the polynomial @var{c}.
+##
+## The formatted polynomial
 ## @tex
 ## $$ c(x) = c_1 x^n + \ldots + c_n x + c_{n+1} $$
 ## @end tex
@@ -31,8 +33,10 @@
 ## @end example
 ##
 ## @end ifnottex
-## and return it as a string or write it to the screen (if @var{nargout} is
-## zero).  @var{x} defaults to the string @qcode{"s"}.
+## is returned as a string or written to the screen if @code{nargout} is zero.
+##
+## The second argument @var{x} specifies the variable name to use for each term
+## and defaults to the string @qcode{"s"}.
 ## @seealso{polyreduce}
 ## @end deftypefn