Email: Do not set the empty name got from database as name content

The activity will restart and get the name from database when rotate screen.
If name is null, do not set username text and the input message will
disappear.

CRs-Fixed: 670717

Change-Id: Ib1fb6724c51f0ecdcfb2b57108cf71ac7b4f991b
Email: Viewing the attachments of the sent emails

The cachedFileUri is a URI of EmailProvider and not allowed to
access from other APP for the security reason. To view the
attachment, a shareable uri is needed.

Use the authority of AttachmentProvider instead of EmaiProvider to
create the cached file URI. Add the new cachedFileUri to the
AttachmentProvider, and add the query(), getType() and openfile()
operation for it.

CR-fixes: 655351

Change-Id: Ib0f990a4d14bc272c278334591e595e312ed77fb
Email: fix sync size spinner text being cut off

Change-Id: Ia5cbdc279fd5299f96a49d6b351ca1eb47fbe21e
Signed-off-by: Roman Birg <roman@cyngn.com>
Email: cmcc cleanup

* Rename enhancement settings to attachment settings
* move select contacts up to general settings
* Make strings clearer

Change-Id: I7740fe698b8efb80823d7ee40db27ab2ef48fc58
Signed-off-by: Roman Birg <roman@cyngn.com>