Improve error handling in libribzip2

[torfmaster]

Provide error types for compression and decompression. There should be

• a type for compression basically wrapping IO errors
• a type for decompression basically wrapping IO errors or a decompression domain specific error

As decompression errors are usually not recoverable the decompression domain specific error could be a flat enum containing the following cases (to be completed)

• selected non-existing Huffman table
• data exceeds block size of 900k (e.g. RLE or ZLE produces unexpectedly long blocks)
• crc errors
• orig_pointer out of bounds

and many more. The errors should come with speaking display implementations. Ideally the CLI should display them instead of just panicking.