Challenge Angular CalcAPP mini-project

Create an app w/ Angular 1.5.8 & Bootstrap that:

Stage 1 (Basic)

• Allow us to introduce two numbers and make the four basic operations

Stage 2 (Error Control)

• Control all exception errors like: Result = NaN || undefined || null...
• Show message indicating pos errors

Stage 3 (History)

• Make and show a history of operations
• Don't add a failed operation to history if the result is NaN, undefined or null

---

Example:

## Extra:

• Clear history
• Config:
  • Round the results as many decimals that user prefers

Resources:

• http://www.w3schools.com/jsref/jsref_sqrt.asp

made by: @agandia9