Add delta apply
Simplify argument parsing
Enable public/private encryption and dep in sodium
Add keypair command to generate pub/priv keys
Save base64 encoded priv/key when gen keypair
Add base64_decode method
Add private key file signing
Replace qsufsort with sais

based on sais-lite [https://sites.google.com/site/yuta256/sais]
Add threaded patch generation
Use base16 format for per file hash
Add arguments for threads, memory limit, and cache dir
Add error if memory limit is insufficient
Add binary diff cache
Add C99 as a requirement to build
Add liblzma dependency
Add lzma iostreams filter
Change compression filter to lzma
Support lzma as shared object if available
Remove BZ2 dependency