Edit event schedule

[Igor Santos]

As suggested by Galvão at the PHPConference, the best way to insert the entire schedule is through batch-importing.

Having the user downloading a .csv file, filling it, and uploading would be a great way to tackle this, initially.

[Igor Santos]

Moving event edit files into a separate folder and adding tabs to the main edit form. refs #74, #75, #76, #77, #137

→ <<cset 376692a9af07>>

[Igor Santos]

Adding simple importer of sessions. reopens #137

→ <<cset f4f5fac84630>>

[Igor Santos]

Displaying basic schedule. refs #137

→ <<cset 43697d23ebb9>>