partial cleanup of include files in gui sources * symbol-information.cc, octave-adapter/octave-event.cc: New files. * documentation-dockwidget.h, history-dockwidget.cc, m-editor/file-editor.h, octave-event.cc, octave-event.h, octave-link.cc, octave-link.h, octave-main-thread.cc, octave-gui.cc, symbol-information.cc, symbol-information.h, workspace-model.cc: Avoid including unnecssary header files.

EXTRA_DIST += \
  m4/module.mk \
  m4/ax_blas.m4 \
  m4/ax_blas_f77_func.m4 \
  m4/ax_lapack.m4	\
  m4/ax_pthread.m4 \
  m4/gnulib-cache.m4 \
  m4/libtool.m4 \
  m4/ltoptions.m4 \
  m4/ltsugar.m4 \
  m4/ltversion.m4 \
  m4/lt~obsolete.m4