added test() method to dimarray/core/core.py
testing: test_all function in progress
core.py, axes.py, metadata.py, _indexing.py and _reshape.py now pass
tests
added kw indexing in separate method take_kw with no risk of conflict
with other parameters
can now do tuple (multi-dimensional) indexing with take, old tuple
definition as slice alias removed (also enhance clarity)