mutualize exceptions
remove implementation
clean and simplify code
Merge branch 'empty-client' of github.com:seblm/xke-memory-client into empty-client

Conflicts:
	src/main/java/fr/xebia/MemoryGame.java
add a README
move project to java8
java7 implementation
makes model fields readable

fields was private
optimize imports
Merge branch 'master' into a-solution