Ability to use an object for performing many replacements in a single call

[garrypas]

I modified the replace function to take a dictionary of key/value pairs as a JSON object and replace them all in one go. For example I have a file with various placeholders that I want to transform. Hopefully this will be useful to other users of this project.

gulpInjectString.replace({
  "{{ key1 }}": "value 1",
  "{{ key2 }}": "value 2"
  // ... etc ...
})