Implement a simple interpreter

[tancheng]

Parses the neura op, and stores the result as float into a map.

• first step towards [P1] An interpreter to run neura ops #5

TODO:

• should support other value types, e.g., vector, tensor
• should handle passed in arguments
• support other neura operations and other dialects if necessary

[ShangkunLi]

Looks good to me.