added mako renderer to setup.py and integration tests for pyramid > 1.5

Before:

    1 horus/tests/test_init.py ...
    2 horus/tests/test_integration.py FFFF..F                                                                            
    3 horus/tests/test_interfaces.py ..
    4 horus/tests/test_models.py .......................
    5 horus/tests/test_resources.py .
    6 horus/tests/test_schemas.py ..
    7 horus/tests/test_views.py ....................................

After:

    1 horus/tests/test_init.py ...
    2 horus/tests/test_integration.py .......                                                                            
    3 horus/tests/test_interfaces.py ..
    4 horus/tests/test_models.py .......................
    5 horus/tests/test_resources.py .
    6 horus/tests/test_schemas.py ..
    7 horus/tests/test_views.py ....................................

Cheers!