Locale update - improve remove, extract, read

[sjoblomj]

• Will now return result from the remove and extract subcommands - previously it always returned 0.
• Properly checking locales when removing, extracting or reading files
• No longer halts on error when extracting. If a file can't be extracted (for example due to incorrect locale), then that will be printed and the extraction of other files continues.
• Test improvements

This should be merged after #136, which should be merged after #134. Until they are merged, the diff will thus be very large.