Fixed identifier of bound functions on node 4

[jordaaash]

Originally detected while using co-redis; thenify breaks libraries that depend on it when using Node 4.x and bound functions are passed to eval/createWrapper.

This is because the function name 'bound ' contains a space, making it an illegal identifier.

This commit fixes this in accordance with the same fix here.

[jonathanong]

can you add a test?

[jordaaash]

There seems to be a problem with Travis relating to Node 0.8, but here is the test output after all commits in this PR:

➜  thenify git:(patch-1) node -v
v4.2.1
➜  thenify git:(patch-1) npm -v
2.14.7
➜  thenify git:(patch-1) npm test

> thenify@3.1.0 test /Users/jordan/Projects/thenify
> mocha --reporter spec



  ✓ fn.name
  ✓ fn.name (bound function)
  ✓ fn(callback(err))
  ✓ fn(callback(null, value))
  ✓ fn(callback(null, values...))
  ✓ fn(..args, callback())
  Promisify
    ✓ should reject errors
    ✓ should reject errors with arguments
    ✓ should return the result

  with callback backward compatible
    fn.name
      ✓ should set function name by default
      ✓ should set name to empty
    fn(callback(err)
      ✓ promise
      ✓ callback
    fn(callback(null, value))
      ✓ promise
      ✓ callback
    fn(callback(null, values...))
      ✓ promise
      ✓ callback
    fn(..args, callback())
      ✓ promise
      ✓ callback


  19 passing (25ms)

[jonathanong]

oh feel free to remove 0.8 from travis. we don't need to support it anymore.

[jordaaash]

Not sure how you like commits structured, but I can squash these if desired.

[jonathanong]

nope these are great because your commits names all make sense 👍

[jonathanong]

merged 1a26a74

[bakineugene]

Hi, is there a reason why this problem have not been fixed for "withCallback" version?

[dead-horse]

fixed in acdcd59

[bakineugene]

thank you