Merge pull request #113 from tkrille/cleanup

[cleanup] switched to new Name#isEmpty() method
[cleanup] remove unnecessary test class
[enhancement] replaced extension type mapping with jpa converter
Merge pull request #114 from davidmoebius/extension_type_convertion

Extension type convertion
[cleanup] made method generic to avoid casts
[cleanup] removed superfluous method
[cleanup] removed instance-of test
[fix] replaced the wrong with the right variable name

Conflicts:
	registration-module/src/main/java/org/osiam/web/controller/ChangeEmailController.java
[cleanup] formatted code & organized imports
Conflicts:
	registration-module/src/main/java/org/osiam/web/controller/ChangeEmailController.java
	registration-module/src/main/java/org/osiam/web/controller/LostPasswordController.java
	registration-module/src/main/java/org/osiam/web/controller/RegisterController.java
[cleanup] did some things mentioned in the comments of #90:

- removed useless comments
- fixed some typos
Conflicts:
	registration-module/src/main/java/org/osiam/web/controller/ChangeEmailController.java
	registration-module/src/main/java/org/osiam/web/controller/LostPasswordController.java
	registration-module/src/main/java/org/osiam/web/controller/RegisterController.java
[fix] fixed BT-28