Upload symfony2 framework.

The exact version is 2.3.2, if anybody cares ;) .
I will remove all the "acme" stuff later.
Generate new "MinePlus\MainBundle", this will hold all the main code.
Disable the default "Acme" routes.
Create new "DashboardController", this will be the default hompage.
Add commonly used assets, and include them in the base template.
Add doctrine migrations to dependencies and register the bundle in the AppKernel.
Add "Installation" section to README.md.
Create CONTRIBUTING.md
Update CONTRIBUTING.md
Create new Use Entity and associated migration.
Remove annotations from DashboardController.

There are so many blog articles describing why annotations in php are evil, and I decided to remove annotations entirely from the application.
Create new SecurityController, associated view, routing and test.
Fix bug in Entity User->getRoles() returning null instead of an array.
Provisionally fix issue causing the user to be de-authenticated.

I don't know if this is really fixed this way, 'cause this piece of code is un-documented, is it?
Use default code for security.

I'll customize the login form later ...
Add the 'Flat UI' Bootstrap theme.

Maybe I'll remove this again later, if it dowsn't make us hapy ;) .
Upload less.js for custom stylesheets.
Upload fonts of the 'Flat UI' bootstrap theme.
Revert "Upload fonts of the 'Flat UI' bootstrap theme."

This reverts commit 33f1dc5f9ddd50db835f1f7f5ddcc7f68fd9c12e.
Add some fonts from out bootstrap theme.