New algorithm for selective dictionary string recycling

Major improvements:

• New algorithm for dictionary string recycling (greatly improves compression)
• Add "exhaustive" testing mode (successive truncation)
• Add cumulative results to test harness

Initial release with pre-built binaries

First version of LZW-AB available with Windows 64-bit binaries (built with MinGW).

Major improvements since 2016 version:

• Extend available maximum codeword size to 16 bits
• Add contexts for the callbacks to facilitate multiple instances
• Create a test harness with integrity verification and fuzzing