Added the following:

- isFulfilled promise method
- isRejected promise method
- isPending promise method

- isPromise ayapromise method (just checks that a then function is defined)
- ayapromise is now a function that returns a promise wrapper to a given
value, if said value is not a promise. Otherwise it returns the promise.

Turned double quotes in single quotes for consistency.
Done the following:

- added tests for all functions and methods added
- fixed error in the ayepromise wrapper function I added
- changed single quotes into double quotes, for consistency.
  (I picked double quotes this time since in the tests files they were
  prevalent)
Version bump