Scala style changes.
Merge remote-tracking branch 'upstream/master'
Merge pull request #6 from gphat/master

Scala-stylify Moe
Remove some strings before method signature.
Methods with only a match should just use match, not wrap it in {}
;s are not needed
Add add wildcard match to Interpreter to catch unknown node types, with
test.
Merge pull request #7 from gphat/master

Minor nits and a warning fix.
Use Option inside MoeObject rather than nulls, as it's more idiomatic
and more useful in the future.
Merge pull request #8 from gphat/master

Use Option in MoeObject
Use Option for MoeClass' superclass.
Merge remote-tracking branch 'upstream/master'
Merge pull request #9 from gphat/master

Use Option for MoeClass' superclass
Clean up MoeObject further and add documentation.

* Use the implicit constructor with a default to reduce complexity
* Add scaladoc to methods and class
* Rename some variables to be more descriptive
* Use named parameters in methods, since this is one of those libraries
  that needs to be read by others and it will change often. Future
  proofing!
Basic contitional expressions support
Merge remote-tracking branch 'upstream/master'
Minor indents fix
Use the correct acronym for SBT
Add build.sbt instead of shipping libs (credit to @non in #2) and fix a
warning.
Optimized elsif conditionals