v0.20

Changes:

- add support for perf-syntax
- check_wmi: add performance data
- check_wmi: add support for empty-syntax
- update check_nsc_web to v0.7.1
- check_service: fix json error
- update windows build framework to wix 3.14 
- improve wmi stability
- add regexp replacement macro post processor
- add if/else conditionals to *-syntax templates
- check_drivesize: does not use parent folder anymore automatically. Use folder=...if required 
- fix windows ps1 wrapped scripts
- check_ntp_offset: add support for other languages
- fix timeout for checks over nrpe