Added a simple test script. Changed the install for includes

    Previously the make install would copy ALL the sources of
    Selwyn in /usr/local/include/memlib changed the behaviour
    so only the headers are copied there.
    The tests are now compiled separatly from the install.sh script.
    They now belong to the tests/test.sh script (which is very
    basic and should change as I get used to CMake), the script
    compile in every possible versions then execute and only test
    the processus exit value.

    CMake now only use global variables and no more relative paths.
    (will maybe not work with Windows "make instal")

    Updated the TODOlist