Simplified AssetGraph.removeAsset and fixed a bug that prevented an asset with a relation to itself from being removed.
Simplified AssetGraph.removeAsset and fixed a bug that prevented an asset with a relation to itself from being removed.

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