AOSP Email app supports reply-to but it's not used for default when using imap.

This commit originates from http://pastebin.com/R0QPpnft, author unknown.

When fetching email, also fetch the reply-to field (when using IMAP),
as it will be used, but currently is not fetched, and thus is not used

Change-Id: I7657b19d643ba5976abdae0aac458633e4297383
Email: Clarify some strings

Change-Id: Icda4add7a05731e35af5f7b207c6507290c10313
Email: Remove unnecessary enable sync size setting

* Determine whether sync size limiting is enabled based on the sync size
  setting itself.
* Database column must remain, as there is no support for deleting
  columns in SQLite.

Change-Id: Ica7808de03dd76bf53f4cfbe8618bacb4859d1b1