- added "spectrum-x-label" and "spectrum-y-label" properties specifying how
  the quantities on the curve axes are called


git-svn-id: svn://svn.code.sf.net/p/gwyddion/code@16840 25697fe4-d644-49b8-9d30-be5465f2adf3
- use axis labels obtained from the spectra object for the graphs


git-svn-id: svn://svn.code.sf.net/p/gwyddion/code@16841 25697fe4-d644-49b8-9d30-be5465f2adf3