Fix various adb error reporting bugs.

`adb install` was writing success to stderr rather than stdout.

Server mismatch messages were going to stdout rather than stderr.

Error messages should consistently start with a lower case letter.

Also improve consistency of syntax error reporting.

Bug: https://issuetracker.google.com/37128706 (adb install success to stdout)
Bug: https://issuetracker.google.com/37140458 (server mismatch on stderr)
Bug: http://b/32413861 (consistency)
Test: ran tests
Change-Id: I0d6cb0c7482bec03483dacefd996644b7a28d273