Small improvement to ol, better numbering

Changed numbering to ol so that it follows the:
1
1.1
1.1.1
1.2
1.2.1
1.3
1.4
2
2.1
etc...
style of numbering.
Specially noticed when using nested lists.
Merge pull request #195 from brunoais/ol-better-numbering

Ol better numbering