Explicitly order all commits

Configuration option (config.toml):

[git]
mergeMessage = "array or string"

Fixes CI builds

It caused more problems than it solved

This fixes #8

Also fixed generator crashing when article was not commited

Moved all not yet promisified files to sitegin/legacy

- When paragraph has image its not p but div.has-image
- You can specify image dimensions in markdown

- Misc crash fixes

 - now I understand how it works ;)

metadata: allow override date and author from metadata
format:
[author]
name = "Name"
email = "my@email.com"
[date]
creation = "2015-07-31"