Lgndr: Prefix files that aren't part of legendary with 'api_'
Lgndr: Return statistics from 'verify_game' instead of parsing the exception
VerifyWorker: Add 'error' signal for exceptions.
Lgndr: Move code segments copied from `prepare_download` back to their original location in `install_game`
Lgndr: Add the LgndrLogHandler at initialization instead of every function.
Lgndr: Move `verify_game` to its original place in `LegendaryCLI`
Lgndr: Change the way DLManager is patched into LegendaryCore proper
Shared: Add singleton for LegendaryCLI, LegendaryCoreSignleton returns core from LegendaryCLI
VerifyWorker: Update to use `verify_game` from `LegendaryCLI` directly
PreLaunchThread: Initialize LegendaryCLI to get LegendaryCore from it
InstallDialog: Update `prepare_install` argument names
