#214 feature/implement replace js function

[0styx0]

Summary

Feature implemented: Users can replace using JS functions. The provided input will run as the return statement to string.replace and can use the same variables mentioned in MDN

Example:

• Replace: dino(saur)
  • Input type: Regular Expression
• With: "great big " + match + " biga" + p1.toUpperCase()
  • Output type: Function

• Result: great big dinosaur bigaSAUR

  Screenshot

  

UI changes:

• Added a warning about executing arbitrary JS in the options page
• Added an "Output Type" select in the sidebar and in the options page featuring options "text" and "function"

This PR addresses issue #214

[0styx0]

@Woundorf thanks for your feedback! addressed all comments