Add usage docs

Added usage docs

Use custom md4 hash

The md4 hash method is not guranteed to be available in the hashlib library. Switched to a custom MD4 implementation for creating the strong checksum. This implementation was found online at its author is mentioned in the md4 module.

rdiff 0.1.2 release

This release has the same feature set as the previous releases.
The main purpose of this release is to correct a mistake while uploading the package to pypi.

The initial rdiff release

This is the first rdiff release. This tool is a native python implementation of the rdiff tool by librsync.

Full Changelog: https://github.com/MohitPanchariya/rdiff/commits/0.1.0