Prevent a "Resource.NotFoundException"

AAPT is a bit too aggressive per default and will kill some needed resources (e.g. forward mail icon). Prevent AAPT from optimizing too much.
Merge pull request #458 from rtreffer/patch-2

Prevent a "Resource.NotFoundException" when building from AOSP tree
Eliminate unused field/parameter
Issue 6280 -- SMTP Setup: ArrayIndexOutOfBoundsException: length=0; index=0

When the outgoing server settings don't require
authentication, userInfoParts.length == 0.