fixed a bug in equals() in CustomField.java

it did not properly compare values list.
added tests.
added field apiKey to the User bean
Merge pull request #96 from taskadapter/ask-custom-equals

#95 fixed a bug in equals() in CustomField.java
update Redmine test data (new Redmine 2.3.3 installation)
Proposed implementation for #102 - Users Groups retrieving
minor safe cleanup
#97 - Update due date format in writeVersion
Merge pull request #98 from francm/master

Update due date format in writeVersion - issue #97
un-ignored couple tests for Versions.
minor cleanup in tests.
change version to 1.22-SNAPSHOT
deleted some invalid javadoc
fixed testGetVersions() test, which was non-deterministic.
replace Maven dependency description with Gradle.
Merge pull request #99 from ciasnmic/master

added field apiKey to the User bean
#99 add test for user.getApiKey()
mark setApiKey() as deprecated to indicate that it should not be used by the client code.
Updates following review:
- added Redmine compatiblity information
- Separated Unit test into two: one for the user's groups retrieving, the other to check adding same group twice works as expected.
Merge pull request #103 from GurvanLd/master

Proposed implementation for #102 - Users Groups retrieving
#102 renamed a test
set version to 1.22 for the release
#105 change equals() method to use id only (all bean classes)

except Changeset class where equals() now uses "revision" field.