Added @TYPE@_vector_div() to divide all elements by scalar
ctest_run will log failed tests in addition to errors ERT-141
1. Fixed bug with optional default_value argument in constructor.
2. Implemented C based __div__()
3. Added tests for mul/div/add
4. Will raise ValueError() if incompatible sizes are combined.
Merge pull request #87 from joakim-hove/tvector-bug-141

Tvector bug 141