Improve events management

[crevoisier]

Add functionalities to enhance event management

•  add an observer to write events synthesis as csv file
• add a simulator to read an events synthesis csv file and produce these events
• add an openfluid tools to generate xml section in domain.fluidx from an events synthesis csv file
• add OpenFLUID.getEvent / OpenFLUID.setEvent in ROpenFLUID package (and other language bindings : Python, JavaScript,...)