Add Multi-Part and Split SMS Configs

PS 2 : Added Split SMS
PS 3 : Cleanup
PS 4 : Fixed Derp!
PS 5 : Fixed Commit msg

Change-Id: I9c9a66ea045a7fb8b20e9d378308eb7d1dc266f6

Conflicts:

	res/values/strings.xml
	res/xml/preferences.xml
	src/com/android/mms/ui/MessagingPreferenceActivity.java
Separate Multi-part SMS setting from size

This does the foll.:

- Separates the toggle from the size (makes more sense)
- Defaults to true, so users find no diff in behavior
- Default convert value for MMS to 7
  (I would suggest that the sprint devices set it via overlay to -1)
- Generalize numberpicker dialog message

Change-Id: I5b6fb33c3cc56a4078d0170a080ccee840afdbf1

Conflicts:

	res/values/strings.xml
	src/com/android/mms/ui/MessagingPreferenceActivity.java