Better travis ci config.

Lifted from https://github.com/codahale/metrics/blob/ca79f9bf26bcc2a0dde8373c3a3fb81f6bf20818/.travis.yml
Benchmark the cost of Spring AOP
Update to metrics 3 beta 2

Changes package names for metrics from com.yammer.metrics to com.codahale.metrics
Update spring framework to 3.2.2 and metrics to beta 3
Added test to show that meteredclasses implementing an interface don't work
Added a new MethodKey to be used in the HashMap. within the Interceptors to identify the called methods
Removed exceptionTypes as field in MethodKey.
A method can't be overloaded by only adding a throws declaration
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