Merge pull request #22 from thyzzv/master

Fixes #21
Make MethodKey package private
Spring 3.2.3
Reformat source
Double-checked locking for creation of registries to avoid synchonrizing
the entire method.
How was scope still hanging around in here?
Eagerly compute and cache hashCode for MethodKey
Add MethodKey.toString
Save some code by correctly assuming that all fields in MethodKey are
non-nullable.
Generalize proxying bean processors.

Turned AbstractProxyingBeanPostProcessor into AdvisingBeanPostProcessor
Removed {Metered,Timed,ExceptionMetered}AnnotationBeanPostProcessor
Limited visibility of bean processors by creating
MetricsBeanPostProcessorFactory
FindBugs didn't like my double-checked locking. :(
Tabify pom
Checkstyle changes

Allow tabs, RightCurly alone, ignore javadoc for now
Update versions of maven plugins
Use same config for findbugs for site
Upgrade caliper to 1.0-beta-1
Add maven enforcer
Bad version for maven-checkstyle-plugin

maven-checkstyle-plugin uses checkstyle 5.6 which removed
the DoubleCheckedLocking check
Resolve all checkstyle errors