Sparse features trainable with hg mira

(In phrase-based Moses)
Output edge scores correctly
Refactor hypergraph output code
template-ise, preparing for chart version
Stub out chart hypergraph output
Implement hypergraph output for chart moses
Fix hypergraph pruning
Fix output of sparse features in hypergraph
Merge branch 'master' of github.com:moses-smt/mosesdecoder