used cppcheck, valgrind on the examples.

fix the C interface free(), the example, the build type select.

update the cppcheck files, add the clang scanbuild script

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>