Added geometry formula shower / calculator Goodie

This is a converted Goodie, the old PR was duckduckgo/zeroclickinfo-goodies#464

**What does your instant answer do?**
This spice shows geometric formulas (e.g. circle area) with a mockup or calculates them if sizes are specified.

**What are some example queries that trigger this instant answer?**
- formula circle perimeter
- calc circle area with radius = 3
- geometry cube volume length 50.6
- calc equilateral triangle perimeter
- formula ball volume
- geometry rectangle area a = 5,2, b = 10
- geometry cuboid volume a: 5; b: 3; c: 4

**Is this instant answer connected to a DuckDuckHack [instant answer idea](https://duck.co/ideas)?**
Yes, https://duck.co/ideas/idea/1053/geometry-calculator.

**Which existing instant answers will this one supercede/overlap with?**
Not known yet

**Are you having any problems? Do you need our help with anything?**
Only improvement questions:
 - The data is static in [geometry.js, line 68 to 365](https://github.com/pixunil/zeroclickinfo-spice/blob/geometry/share/spice/geometry/geometry.js#L68-365), maybe perl could fetch the shape wanted in a separate js file

- it would be great to get the hover color defined by the user in settings

**Checklist:**

- [x] Added metadata and attribution information
- [x] Wrote test file and added to t/ directory
- [x] Verified that instant answer adheres to design guidelines(https://github.com/duckduckgo/duckduckgo-documentation/blob/master/duckduckhack/styleguides/design_styleguide.md)
- [x] Tested cross-browser compatability *with support tables*

 Browser | supported versions | unsupported feature for older versions
 ----|-----|----
 IE | 10+ | classList
 Firefox | 8+ | classList
 Chrome | 8+ | classList
 Safari | 5.1+ | classList
 Opera | 11.5+ | classList
- [x] Tested live only on Linux (Mint) 64-bit, Firefox 33
@pixunil Yeah it's a problem even on `onShow`. We still have to track down the bug, but what I did is put the `.load` event in the `onShow`: https://github.com/duckduckgo/zeroclickinfo-spice/blob/master/share/spice/currency/currency.js#L147