Use a precompiled version of CMake 3.0.2.

Will speed up the Travis build.
Merge pull request #6 from Neki/topic/bf_travis_cmake

Use a precompiled version of CMake on Travis.
Temporary commit (with code example).

Will be cleaned/splitted later. Not tested with cpplint.
Fix confusion on C++ const syntax.
Remove dummy file.
Clean the events definition.
Explicit enum convertion to int.
Implement serialization/deserialization according to the current def. of events.
WIP on the client network manager.
Add a first, very basic, serialization test.
Update gitignore.
Do not use raw pointers in the client NetworkManager.
Move the serialize method to the Event class.
Test the event id serialization/deserialization.
Preoperly deserialize the client version.
Add comment.
Add operator== for events.
Add "deserialized event == serialized event" test.