Fix height-varying for speakers grid

[Igor Santos]

Whenever speakers have a different image height, or more lines of bio/themes, their block gets higher, what in turn makes blocks from the second line get out of place. A fix for this could be having an outer div with a fixed maximum height, making all blocks from that line have the same height, without moving them towards the horizontal center.

[Igor Santos]

Fixing speakers grid. closes #40

→ <<cset 5735417035a3>>