docs/debugging: use bzip2 for consistency with the new ticket form (Thanks x33a)
docs/debugging: update version numbers
docs/debugging: explain how to enable logging on the fly
docs/debugging: include supported version, recommend --moreversion
docs/debugging: merge the debug symbols/backtrace section

We rarely have crashes, almost always we just need logs.
docs/debugging: use a version command that will work with i3 < 4.3
enable shmlog when invoked as i3-with-shmlog, install symlink + .desktop file
Merge branch 'docs-debugging'
Merge branch 'master' into next
install i3-with-shmlog.xsession.desktop, overwrite symlink if it exists
Merge branch 'docs-debugging'
Merge branch 'master' into next