Xdeps version 0.5.0

Changes:

• Cythonize refs.py to gain performance.
• Print only shapes of arrays in the table, and by default put their columns at the end.
• Fix plotting example and add more options for plotting.
• Fix minor bugs relating to ensuring list type for _col_names in table.
• Refactoring of unused code.

Full Changelog: v0.4.3...v0.5.0