add --config global option. allows to set hgrc option on command line.
syntax: --config section.name=value
also add new test-globalopts to test all global options in one place.
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
removing b
this update spans a branch affecting the following files:
b
aborting update spanning branches!
(use 'hg merge' to merge across branches or 'hg update -C' to lose changes)