Kiwix/ZIM incremental updates/24-30 June report

As part of Gsoc(weeks 2,3,4), the zimpatch tool was developed. The zimpatch tool is used to obtain the end_file using the start_file and the diff_file. It takes two zim files, start_file and dikff_File as input and produces the end_file as output.

Logic: start_file + diff_file = end_file.

Code: https://github.com/kiranmathewkoshy/zimpatch

This is a major milestone in the project. the next few weeks will involve testing zimdiff and zimpatch, and upon completion, these tools will be incorporated into Kiwix.