Merge pull request #4563 from mark-lazarides/ftr/update-twincat3-libs-dir-update

modifies lib exclude, adds example lib include

TwinCAT3.gitignore

@@ -43,6 +43,10 @@ LineIDs.dbg.bak
 **/_Deployment/
 **/_Repository/
 
+# To include a specific library directory (i.e. third party/custom libs), 
+# use pattern `!/**/_Libraries/<directory name>/` i.e. `!/**/_Libraries/www.tcunit.org/`
+# 
+
 # VS Shell project specific files and folders
 **/.vs/
 *.~u