strip InvocationTargetException from stack traces

We really just care about the cause.
Merge pull request #54 from adennie/fix-comparable-warning

fix compiler warning about use of unparameterized Comparable declaration...
fixed comment block indentation
restore blank lines in copyright/license comment header.
Merge pull request #55 from adennie/base-interface

Add OttoBus base interface, and have Bus implement it.
Merge pull request #48 from adennie/issue47

fix issue #47 - run enforce goal during Eclipse builds.
Merge pull request #46 from adennie/checkstyle-line-separator

add lineSeparator property to NewlineAtEndOfFile checkstyle module to av...
Merge branch 'better-conflicting-producer-exception' of https://github.com/adennie/otto into adennie-better-conflicting-producer-exception
Package scope the variable directly.
Merge branch 'master' of github.com:square/otto
Merge branch 'unpack_ites' of https://github.com/loganj/otto into loganj-unpack_ites
Formatting.
Space.
Two space poms.
Revert "Change ThreadEnforcer ANY to NONE for clarity."

This reverts commit 4f8c074d4a8bb146af5779fe7ca9841a6d01c8bd.

Conflicts:
	CHANGELOG.md
	library/pom.xml
	pom.xml
	sample/pom.xml
Revert "Add OttoBus base interface, and have Bus implement it."

This reverts commit 74b789a0b970689de70a8990e2ad1ce7eba8478e.

Conflicts:
	library/src/main/java/com/squareup/otto/OttoBus.java
Update change log, version.
Mention concurrency fix in CHANGELOG.
Update documentation
Fix Javadoc tag. Avoid needless object creation.