Deprecate readWav

[vincentvanhees]

After the next release of R package GGIR, function readWav can be deprecated, because:

• The wav files are hardly used, because researchers usually also have the .cwa files and work with them directly.
• The way the wav files are created seems to affect the file header format, which complicates robust extraction of header information.
• Does not work for AX6 sensors yet.
• Extraction of temperature data is currently skipped.
• Code itself is messy and would need tidying up.

To do:

• [ ] Remove R function
• [ ] Remove .Rd documentation
• [ ] Remove dependencies (tuneR)
• [ ] Remove from README file