Release 1.6.0beta1.
Release 1.6.0beta1.

assetgraph/assetgraph,papandreou/assetgraph,jscinoz/assetgraph,jscinoz/assetgraph,jscinoz/assetgraph,papandreou/assetgraph,papandreou/assetgraph,slang800/assetgraph,slang800/assetgraph