lightr 2.0.0

Major breaking changes

• the low-level parsers to parse individual files have been renamed from the
  previous naming scheme lr_parse_<fileext>() to
  lr_parse_<brand>_<fileext>() (#72). This gives us flexibility to use
  different parsers when two or more brands use the same file extension but
  actually different formats.

New features

• Parsing for binary files produced by Avantes AvaSoft 8.4 has been restored in
  lr_parse_avantes_rfl8(), lr_parse_avantes_irr8(),
  lr_parse_avantes_raw8().
  Thanks to Allison Shultz, Lindsey Swierk, Raphaël Scherrer, and Michaël
  Nicolaï for providing feedback and test files.
  Thanks to Avantes for providing the file format documentation.

Minor changes

• Performance of high-level functions (lr_get_spec(), lr_get_metadata()) and
  some low-level parsers (csv, ttt, trm, jaz, jazirrad) has been improved.