Abide verification framework

First internal release of the abide framework that features:
- reflective rule and analyzer loading
- abide compiler plugin
- basic cli that provides 4-phase compilation with abide on top
- sbt plugin sketch (needs version management)
- traversal analyzer that applies single-traversal rules
- scoping analyzer that applies single-traversal rules and provides scoping and/or path information
- a few example rules and doc on how to add more

This kind of failure denotes a bug in Abide, or in the way a rule was written? In other words, would it make sense to recover? `sys.error` is almost never the right thing, for example if this code runs inside an IDE, this will exit the running JVM (including the IDE).