add containsKeys to MapAssert
unquoted string, not sure
use parent pom 1.2.1
fixes #27
rename tests
rename test methods
with example
javadoc.. I was tired...
move functions to Comparables
reuse functions
CONTRIBUTING.md minor improvement
Fixes #12 : MapAssert.containsKey should use varargs params
Fixes #12 : MapAssert.containsKey should use varargs params

Conflicts:
	src/main/java/org/assertj/core/api/MapAssert.java