Fixes Issue 188

Fixes Issue 394
Fixes Issue 763

Completely new Services architecture providing proper Service
lifecycle management.
  Long running tasks in MailService are executed in a separate thread,
  but the service is not stopped until the tasks are complete.

  SleepService for providing synchronous sleeps with proper WakeLock
  integration.

  Mail polling logic moved from MailService to PollService

  PushService to keep application from being killed while push is
  running.

Improved logging of IMAP protocol, including logging folder name,
thread and connection hashcode.

Don't put a failed connection back into the IMAP mConnections
storage. 

IMAP IDLE uses new SleepService for delaying between failed connection
attempts (allows phone to sleep and provides better reliability)

Use a ThreadLocal for ImapPusher wakelocks

Component enablement/disablement in Email is done only when components
are out of phase with desired state. (Issue 188)