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/unmkpp.m	Mon May 04 14:22:02 2015 -0700
+++ b/scripts/polynomial/unmkpp.m	Mon May 04 21:50:57 2015 -0700
@@ -20,6 +20,7 @@
 ## @deftypefn {Function File} {[@var{x}, @var{p}, @var{n}, @var{k}, @var{d}] =} unmkpp (@var{pp})
 ##
 ## Extract the components of a piecewise polynomial structure @var{pp}.
+##
 ## The components are:
 ##
 ## @table @asis
@@ -27,11 +28,11 @@
 ## Sample points.
 ##
 ## @item @var{p}
-## Polynomial coefficients for points in sample interval.  @code{@var{p}
-## (@var{i}, :)} contains the coefficients for the polynomial over
-## interval @var{i} ordered from highest to lowest.  If @code{@var{d} >
-## 1}, @code{@var{p} (@var{r}, @var{i}, :)} contains the coefficients for
-## the r-th polynomial defined on interval @var{i}.
+## Polynomial coefficients for points in sample interval.
+## @code{@var{p} (@var{i}, :)} contains the coefficients for the polynomial 
+## over interval @var{i} ordered from highest to lowest.  If
+## @code{@var{d} > 1}, @code{@var{p} (@var{r}, @var{i}, :)} contains the
+## coefficients for the r-th polynomial defined on interval @var{i}.
 ##
 ## @item @var{n}
 ## Number of polynomial pieces.