New transformer model

new transformer model
Merge pull request #207 from vanroyj/issue205_transformerLoss

New transformer model
Updated graphical representation of transformer models
Included voltage source in Transformer_MvLv model
Updated Grid3PGeneral.mo for new transformer
updated electric graphics
updated electric graphics
Saved Electric.Distibution not as a single file for github
Saved Electric.Photovoltaics not as a single file for github
Saved Electric.Batteries not as a single file for github
Saved Electric.Data not as a single file for github
Saved Electric.BaseClasses not as a single file for github
updated all examples to new transformer model
Merge pull request #216 from open-ideas/issue205_transformerLoss

Issue205 transformer loss