Reading far data written with old pyfar version will fail in the future

[f-brinkmann]

General

• pyfar version: 0.5.2

Description

After deprecating the old coordinates Class in 0.8.0, new pyfar Version will fail in reading old Coordinate objects. I suggest the following as a trade-off between usability and effort

• write the pyfar version to each .far file
• always read the version first
• everything else should be encapsulated in a try statement
• if reading the data fails, an error with a hint to the pyfar version that was used to save the data is raised