SNClient

Changes:

- write startup errors to default logfile
- add check_os_updates
- check_files: fix skipping folder to early
- check_eventlog: fix using event id
- check_drivesize: add freespace-ignore-reserved option
- fix wrapped scripts not found
- fix check_drivesize using random volume for sub path
- fix check_drivesize using root folder when checking non-existing path
- fix perf-config when using REST API
- fix timeout handling (fixes #96)

Changes:

- fix crash on windows when parsing empty args (#88)
- check_ntp_offset: support more ntpq tally codes

Changes:

- support += operator in config files
- create logfile folder unless it exists
- update windows exporter to 0.25.1
   - i386 still uses 0.24 since thats the last supported version
- fix check_process username being empty sometimes
- fix check_cpu_utilization calculation
- fix automatic log rotation on windows