Mms: Remove text from notification

Rationale:

 - The descriptive text is often too long to fit, on many
   languages. You'll get part of a word, and and ellipsis
   in such cases.

 - The current icons adequately provide meaning to the
   actions they represent.

This idea is not mine, it surfaced some weeks ago, at
 #cyanogenmod-dev. There was a discussion about the need for
desriptive text for these actions, for the reasons above.

Since nobody submitted any patch for that yet, there it is.

Change-Id: I5b628988273363b1a7bfa57de93cc6f70a0f67b5

Conflicts:

	res/values-cs/strings.xml
	res/values-da/strings.xml
	res/values-de/strings.xml
	res/values-el/strings.xml
	res/values-es/strings.xml
	res/values-fi/strings.xml
	res/values-fr/strings.xml
	res/values-hr/strings.xml
	res/values-hu/strings.xml
	res/values-it/strings.xml
	res/values-iw/strings.xml
	res/values-nl/strings.xml
	res/values-pl/strings.xml
	res/values-pt/strings.xml
	res/values-ro/strings.xml
	res/values-ru/strings.xml
	res/values-zh-rCN/strings.xml
	src/com/android/mms/transaction/MessagingNotification.java