v0.3.0

• remove pbkdf2_hmac import;
• remove pbkdf2_hmac() from the final step;
• remove dklen output parameter; output size is always 64-byte now;
• some other simplifications in the code;
• update README.md.

v0.2.0

• Remove space_mib and passes default values;
• Refine MAX_SPACE_MIB value;
• Update docs.

v0.1.0

Initial release.