updated the base layout to use bootstrap3

I've updated the included template with bootstrap3. This is not an attempt to make a kick ass design. Authors would still need to overwrite these templates. Also the forms are not styled yet.

Another update is in the translations file. There is an unneeded (and from my experience not working) string -message_info so i deleted that one. I only did that for the english version for now.


# New template
![rsz_1inbox](https://f.cloud.github.com/assets/3365006/1348357/21514202-36c4-11e3-909c-71e6d99c0991.png)
![rsz_message](https://f.cloud.github.com/assets/3365006/1348358/2e8ef7ca-36c4-11e3-81de-26bf68308df9.png)

# Old template
![rsz_inbox_old](https://f.cloud.github.com/assets/3365006/1348383/da6e8e2a-36c4-11e3-83df-44ece843cbe0.png)
![rsz_message_old](https://f.cloud.github.com/assets/3365006/1348386/df687aa8-36c4-11e3-86ff-739e949b53d7.png)