Split the repository

[ZyX_I]

Suggested split:

• _vim-pi-tools: all scripts used to create the database or work with it. They can be used on ones own risk: no promises about keeping backward compatibility.
• _vim-pi-data: data for tools that should only be used by scripts from _vim-pi-tools.
• vim-pi: public data for plugin managers.
• vim-pi-documentation: public documentation.
• vim-pi-utils: utility functions for use by plugin managers. Public, versioned (with official releases) and documented in vim-pi-documentation.
• vim-pi-descriptions: saved plugin descriptions, used for searching. Not in vim-pi repository because they will greatly increase its size.
• vim-pi-legacy: this repository. Kept for a few month until everybody migrates to new database format.