dispatch: properly handle relative path aliases used with -R (issue2376) This ensures the repo config is read relative to the repo root during dispatch.

dispatch: remove superfluous try/except when reading local ui config ui.readconfig() already handles IOError in this case.

test-globalopts: test hg -R file:// and hg -R path-alias

hgk: remember main window position

alias: back up and restore commands.norepo before checking for shell aliases

tests: unify test-check-code