Support cache policies in default properties files
Support cache policies in default annotations
add missing license headers
Introduce specialized null component exception
Improve injection point toString methods

This tries to make the injection point toString methods map more directly to Java source.
Provide more descriptive injection exceptions
Add missing license header
Add logging to rule-based bind function
Improve injection failure error reporting
Add accessor methods to DAGNodeBuilder
Add tests for DAG node builder accessors
Add class loader utility tests
Improve class proxy test level

- Add tests for equality
- Use ClassLoaders.inferDefault to find class loader
Merge branch 'feature/elehack-error-reporting'

Conflicts:
	src/main/java/org/grouplens/grapht/InjectionException.java
	src/main/java/org/grouplens/grapht/reflect/internal/InjectionProviderImpl.java
Merge pull request #91 from elehack/feature/elehack-property-cache-policy

Support cache policies on defaults