localrepo: fix status() typos from 854b907527e5a and 97c12b1ed1e0

context: trigger missing username warning only when necessary

localrepo: do not modify a dictionary being iterated in status()

dirstate: fix _droppath() typo from 80605a8127e0

Add test for case folding issues

Sort removes first when applying updates (fixes issues 750 and 912) This change ensures that removes happen first in applyupdates(). This avoids issues where we try to make a case-only rename of a file on a case insensitive system. Without this patch, the add of the new name happens before the remove of the old one - which results in the file not existing, as the two names are effectively the same. With the patch, the old name gets removed then the new one gets added, which is always safe.

Added missing --config global option to zsh_completion. The global options --encoding and --encodingmode where also added. Without these options some functionality breaks. Also added basic completion for config items for the --config option.