Simple encryption service Goodie

**What does your Instant Answer do?**
Provides a simple crypto service to encrypt and decrypt a string using the RC4 algorithm.

**What problem does your Instant Answer solve (Why is it better than organic links)?**
Provides way to pass sensitive info from one user to another just using their browser and a preshared key.

**What are some example queries that trigger this Instant Answer?**

crypt encrypt key string
crypt decrypt key string
crypt en key string
crypt de key string

**Which communities will this Instant Answer be especially useful for? (gamers, book lovers, etc)**
Mostly sysadmins and people that need to pass sensitive information around, like passwords or credit card numbers.

**Is this Instant Answer connected to a DuckDuckHack [Instant Answer idea](https://duck.co/ideas)?**
Yes, https://duck.co/ideas/idea/1463/simple-encryption-service

**Which existing Instant Answers will this one supercede/overlap with?**
None that I know.

**Are you having any problems? Do you need our help with anything?**
Not so far, maybe after more testing problems can arise :)

**Where did you hear about DuckDuckHack? (For first time contributors)**
On the news, about 2 years ago.

**What does the Instant Answer look like? (Provide a screenshot for new or updated Instant Answers)**

![screen shot 2014-11-26 at 6 51 29 p m]
(https://cloud.githubusercontent.com/assets/4934646/5210590/b5b3c5b4-759d-11e4-9166-4c49932f5adf.png)



## Checklist
Please place an 'X' where appropriate.

```
[X] Added metadata and attribution information (https://duck.co/duckduckhack/metadata)
[X] Wrote test file and added to t/ directory (https://duck.co/duckduckhack/goodie_tests)
[X] Verified that instant answer adheres to design guidelines (https://duck.co/duckduckhack/design_styleguide)
[X] Verified that instant answer adheres to code styleguide (https://duck.co/duckduckhack/code_styleguide)
[X] Tested cross-browser compatibility

    Please let us know which browsers/devices you've tested on:
    - Windows 8
        [] Google Chrome
        [] Firefox
        [] Opera
        [] IE 10

    - Windows 7
        [] Google Chrome
        [] Firefox
        [] Opera
        [] IE 8
        [] IE 9
        [] IE 10

    - Windows XP
        [] IE 7
        [] IE 8

    - Mac OSX
        [X] Google Chrome
        [X] Firefox
        [] Opera
        [X] Safari

    - iOS (iPhone)
        [] Safari Mobile
        [] Google Chrome
        [] Opera

    - iOS (iPad)
        [] Safari Mobile
        [] Google Chrome
        [] Opera

    - Android
        [X] Firefox
        [X] Native Browser
        [X] Google Chrome
        [] Opera
It's better to make the triggers more explicit. If we know we only want to handle queries of the form "rc4 encrypt", "rc4 en", etc lets just make those the triggers.

Then in our handle statement, we just need to make sure our remainder only contains a key and candidate string