AND gate code generation test
codegen tests for OR and NOT
variable name fixes
Refactored out const fields

In preparation for the serialization step.

And I'm pretty sure someone will ask, so:
Interface fields have implicit public static final modifiers and this is a
common pattern for declaring constants.
Merge remote-tracking branch 'upstream/master'
Whoops it looks like I did fail to merge

Should be correctly merged now... hopefully.
test refactor: add schematicToVHDL() helper
test refactoring: findBlock(), countMatches()
this is still WIP and does not work yet
corrected logic error
checkstyle fixes and further refactoring
all TestVHDLCodeGenerator test cases refactored
Merge pull request #165 from mtrberzi/backend-tests

Backend tests: AND, OR, NOT
Rename typo
Merge pull request #166 from maxqchen/master

Refactored out const fields