fix PC language

fixing comments

instructions on creating a private installation

postgress: reduce the number of open connectins to fit under default …

…limit

adding ukrainian translations

Merge pull request tinode#878 from tinode/session-sub-race-dev

Fix a race condition around Session.subs.

rebuilt python modules

add TODO for file serving over gRPC

fix web attachment downloads by adding Content-Disposition header

adding postgress to docker-release.sh