Release 0.2 planing

[puzrin]

• check coverage report, add the rest of tests if necessary (errors, especially in deflate)
• gzip custom headers write
• cleanup structures (useless fields in gzip header and so on)
• review all commented code lines, and add explanation, why those not needed.
• rename variables (see consider change var names  #19)
• suggorates support for strings
• cleanup strange api methods like deflatePrime and others