Compatibility fixes for Octave 3.8.
- no longer use OCTAVE_QUIT in MEX files; this seems now only possible in oct-files. (Ref #304) - do not build linsolve.oct on Octave >= 3.8, it is available natively. - do not add strjoin.m to the patch on Octave >= 3.8, it is available natively. - default_save_options has been renamed save_default_options.