Python count doesn't count missing values
numpy count treats nan as missing value
TableSymbol -> Symbol
test 3d->1d numpy reduction
Merge pull request #728 from mrocklin/count-none

Count is the number of non-null elements
Merge branch 'master' into array-reductions

Conflicts:
	blaze/compute/tests/test_numpy_compute.py
Merge branch 'master' into h5py-compute