Support for LaTeXTools build output, show build output on error only

This is based upon the Commit 2e0e7c186aeccd1c09347061b5b191bab5c2f8f6 by @jonwingfield, to get disappearing build output panel.

Shows the panel automatically if errors were present in the build.

Adapted the code to support LaTeXTools and their weird build outputs (I sent them a pull request sent for compatibility)