Merge remote-tracking branch 'upstream/master'
Fix iOS 8 support and use libc++ instead of libstdc++
Revert perf stuff
Don't install cmake on travis
Merge pull request #797 from yuklai/master_sessionSwitchReduce

Reduce chance of session (connection) switch in MCIMAPAsyncSession.cc
connection of an imap operation is now set when it's started (#783)
Fixed build issue
Fixed some memory leaks
Fixed memory leak (fixed #794)
Updated to libetpan 01b3b3b83d2b8651c0279018d4e48061509494eb
Added urgent accessor on ObjC API
Fixed crash on disconnection
Added entries for Comcast, Verizon and RCN
Fixed addressWithIMAPAddress for drafts with bad address in to/cc/bcc fields
Merge pull request #804 from rlaferla/patch-6

Added entries for Comcast, Verizon and RCN
Add sdk 7.1 and 8 to build-mailcore2-ios
Merge branch 'master' of https://github.com/MailCore/mailcore2 into iOS8AndLibCpp
Recognize multipart/signed content type
use NS_ENUM and NS_OPTIONS
Merge pull request #810 from bitlogica/master

use NS_ENUM and NS_OPTIONS