Use a variable to explicitly trust global config files

Revert almost all of 5be434785317; add a test Because of file copies, we should update the manifest dict only after committing all files.

avoid unnecessary copy merges

white space and line break cleanups

Merge with crew.

Use nullrev+count instead of count-1 in a newly introduced expression. Before that repo.changelog.tip() was used, but this yields a node. Of course many more places should be changed like this, this was just done as an example.

commands.docopy: pay attention on whether paths use "/" or os.sep