Merge pull request #114 from pakozm/devel

Devel
Added ann.graph package and its first draft implementation
Added unit test
Debugging test
Debugging ann graph
Improving ann.graph. Added ann.graph.bind component. Added ann.graph.sum component.
Solved bug at matrix __div metamethod. Solved bug at autodiff __div operation. Simplified adadelta code, now it has worst efficiency but better legibility. Added Beale's function test in optimizer.
Changed test name
Updated references
Merge branch 'master' into ann_graph
Solved minor problems with rawget and format style
Merge pull request #116 from pakozm/ann_graph

ANN graph branch