update requirements
move Parser class in eventviz.parsers.__init__
rework parsers base classes organization
modify the way event's indexes are defined
setup indexes on application startup, not on each event insertion (+ no need for indexing direction)
fix bug where parsers listing didn't work
display an arrow in front of current project in projects list
remove leftover endif statement in template
prefix all databases with "eventviz_" - fixes issue #3
remove drop_db management command to drop_project (more meaningful)
fix forgotten non-prefixed database names