Write a precommit hook to update changelog and plugin version from git history

[Ri0n]

Basically having json files with metadata now allow to update their properties dinamicaly on git commit.
So we can a git hook which automatically add entries to the plugins' changelogs.
and then we can make a script which will read recent changlogs, detect if it worth to make new versions relying on the changelog and git history and dump the versions of the changes plugins in their json files.
Also the json file may keep changes for just the latest version.

[tehnick]

Manually written changelog looks much better than automatically generated one based of git commit messages...