RPED buffed & updated

* RPED can store 7 more parts (buffed from 14 to 21)
* RPED displays contents with numbers, just like ore or botany satchel.
* RPED can apply parts to machine frames.

RPED's sprite needs work. I tried to resprite it in machinery style:
![rped](https://cloud.githubusercontent.com/assets/3888532/4106726/46ef3d62-31bd-11e4-8c30-2d41cdeac272.png)
Replace or not?