OBMFULL-6174 rename HtmlToText to TextToHtml

	(backport from OP-108)

Conflicts:
	java/sync/opush/push-mail/src/main/java/org/obm/push/OpushMailModule.java
OBMFULL-6174 rewrite test class using EasyMock Control

	(backport from OP-108)

Conflicts:
	java/sync/opush/push-mail/src/test/java/org/obm/push/mail/MimePartSelectorTest.java
OBMFULL-6174 create a HtmlToText transformer and fix the selection policy

	(backport from OP-108)

Conflicts:
	java/sync/opush/mail-backend-interfaces/src/main/java/org/obm/push/mail/bean/NameSpaceInfo.java
	java/sync/opush/pom.xml
	java/sync/opush/push-mail/src/main/java/org/obm/push/OpushMailModule.java
	java/sync/opush/push-mail/src/main/java/org/obm/push/mail/BodyPreferencePolicy.java
	java/sync/opush/push-mail/src/test/java/org/obm/push/mail/AnyMatchBodyPreferencePolicyTest.java
	java/sync/opush/push-mail/src/test/java/org/obm/push/mail/MimePartSelectorTest.java