renamed default column names to C1,C2,…,CN from 0,1,…,n
Updated python tests to work with new default column names in VAs (C1,C2,…,CN instead of 0,1,…,N)
Merge branch 'master' of github.com:0xdata/h2o
PUB-113: fixed problem with conflicting names, now you get an exception if you attempt to parse data with duplicate column names.
Merge branch 'master' of github.com:0xdata/h2o

Conflicts:
	py/testdir_single_jvm/test_GLM_syn_eqns_data.py
	src/main/java/water/fvec/ParseDataset2.java