add coverage on travis
closes #118
Merge branch 'twillouer/issue-118'

Conflicts:
	src/main/java/org/assertj/core/api/AbstractDateAssert.java
	src/test/java/org/assertj/core/internal/DatesBaseTest.java
javadoc improvements
Fixes #118 : Use same error message as assertj-joda-time for consistency
Remove references to Fest