Mess with the updater again.
Fix logging string derp on OSX
Some more updater fixes

Paths were wrong - still used work directory instead of root
Add an option to force using local updater binary (for updater development)
More updater fixage

Preserve --dir parameter after updating
Allow more than one copy of a command line parameter in MultiMC
Linux runner script no longer changes current directory, which allows '--dir .'
Fixed unit tests, removed the obsolete one (for some legacy updater command line params that were also removed)
[fixes 63127704]
Merge branch 'develop' of github.com:MultiMC/MultiMC5 into develop
Merge branch 'updater-tweak' into develop