doc: Spellcheck documentation ahead of 4.4 release. * aspell-octave.en.pws: Add new words to Octave-only spelling dictionary. Remove exception words which are no longer used in manual. * basics.txi, bugs.txi, func.txi, geometry.txi, install.txi, matrix.txi, package.txi, plot.txi, poly.txi, preface.txi, quad.txi, sparse.txi, strings.txi, vectorize.txi, data.cc, defaults.cc, file-io.cc, pinv.cc, quadcc.cc, qz.cc, rand.cc, schur.cc, syscalls.cc, sysdep.cc, toplev.cc, amd.cc, audioread.cc, colamd.cc, dmperm.cc, symrcm.cc, quadgk.m, quadl.m, imfinfo.m, rgb2gray.m, javachk.m, usejava.m, unpack.m, fzero.m, glpk.m, pqpnonneg.m, stemleaf.m, print.m, polyfit.m, blackman.m, bicgstab.m, cgs.m, eigs.m, pcg.m, tfqmr.m, gallery.m, rosser.m, toeplitz.m, vander.m, isstrprop.m: Add @nospell{} macro around proper names and other words which aspell should not check. Correct misspellings identified by aspell.

--- a/doc/interpreter/vectorize.txi	Mon Mar 26 22:54:24 2018 +0200
+++ b/doc/interpreter/vectorize.txi	Mon Mar 26 10:45:04 2018 -0700
@@ -259,7 +259,7 @@
 @section Broadcasting
 @cindex broadcast
 @cindex broadcasting
-@cindex BSX
+@cindex @nospell{BSX}
 @cindex recycling
 @cindex SIMD
 
@@ -431,7 +431,7 @@
 A note on terminology: ``broadcasting'' is the term popularized by the
 Numpy numerical environment in the Python programming language.  In other
 programming languages and environments, broadcasting may also be known
-as @emph{binary singleton expansion} (BSX, in @sc{matlab}, and the
+as @emph{binary singleton expansion} (@nospell{BSX}, in @sc{matlab}, and the
 origin of the name of the @code{bsxfun} function), @emph{recycling} (R
 programming language), @emph{single-instruction multiple data} (SIMD),
 or @emph{replication}.