Clear up the project position on licensing and contributions

Signed-off-by: Luker <luker@fenrirproject.org>

bring the README up to date with the last changes

Signed-off-by: Luca Fulchir <luker@fenrirproject.org>

lots of bugfixes, also due to the creation of a couple of examples
for the C and C++ interface. Updated documentation accordingly

Signed-off-by: Luca Fulchir <luker@fenrirproject.org>

Add the "tests" target and use lstlisting

Signed-off-by: Luca Fulchir <luker@fenrirproject.org>

Also small diff to documentation

Signed-off-by: Luca Fulchir <luker@fenrirproject.org>

cppcheck might come in handy, so let's keep the instructions
and suppressions for everyone.

Signed-off-by: Luca Fulchir <luker@fenrirproject.org>