server: add support for adding meetings

Signed-off-by: Valentina Manea <valentina.manea.m@gmail.com>
server: add support for meeting interogations

Signed-off-by: Valentina Manea <valentina.manea.m@gmail.com>
server: add support for canceling a meeting

Signed-off-by: Valentina Manea <valentina.manea.m@gmail.com>
server: save current database

Signed-off-by: Valentina Manea <valentina.manea.m@gmail.com>
Merge branch 'master' of https://github.com/PDSD-2014/georgescu-manea-bican