Flowchart using canvas

Basic Description: Create flow chart like diagram using canvas, with predefined node types, specific relation validations, and ability convert the chart drawing to and from JSON object supplied on the canvas. Requirements: 1. Each node will be represented by a JSON object. 2. The whole diagram will be represented as an array of each node. 3. Ability to use drag and drop of nodes on canvas. 4. Create connection between nodes in the canvas and reflect how they relate in the JSON object. 5. Validate relations between nodes where some nodes cannot be connected to specific type of nodes. 6. Certain node types (mission type, notification type) will have the templates created in another form in addition to the details added while creating the node, while other types (coin type, delay type, split decision type) will have the value set only while creating the node.