Random variable assignment

while working on the random variable assignment user story, the initial autogen code for my diagram had all sorts of invalid ruby. this is an interim push towards my user story, but should be useful for everyone across the board.

* remove instances of the following when pins are primitive types
```ruby
require_relative('.rb')
```
* move opaque ruby code in between return value initialization and return
* add default values for primitive return value types
```ruby
blah = .new
```

* [Jenkins](https://76.230.136.103:8085/job/jon-code-fixup/54/)