Bug 901926 - [Email] Email app stops working if attachment contains an IMAP literal. r=asuth

(co-authored with asuth)
Merge pull request #238 from mcav/imap-parsing-bug-901926

 Bug 901926 - [Email] Email app stops working if attachment contains an IMAP literal. r=asuth
Bug 883464 - [email/IMAP] Have imap.js stop entering IDLE state, avoid spamming non-IDLE servers with NOOPs. r=asuth
Merge pull request #245 from mcav/disable-idle-bug-883464

Bug 883464 - [email/IMAP] Have imap.js stop entering IDLE state, avoid spamming non-IDLE servers with NOOPs. r=asuth
Merge branch 'master' into bug892519-email-bg-notify
Review feedback: do not skip folder sync, make sure cronsync's syncAccount waits for server ops to finish, and that universe's waitForAccountOps properly exits early when not online or if the account is not enabled