reverted 'tests: platform prefix for light CodeInsight tests'
IDEA-CR-1100 move RequestBuilder to top level
IDEA-CR-1100 rename to productNameAsUserAgent
don't infer that simple getters are pure: currently it provides no value for the user
perform commit command with hgRepository instance as argument instead of VF

* tests fixed
* unnecessary checks removed
preserve folding model consistency on document change - remove fold regions which become equal
vfs: consistency checks on file operations
IDEA-CR-1106 don't include headers to error message by default
simplify