bin/.gitx: fix build dir in ~/src/github
bin/after-co-ln-s.sh: make sure unstable version of offlineimap is used
bin/get-used-files: do not try to edit the tmpf
bin/ps-killall: make it safer to use
bin/sawfish-auto-start: fix pwd

Signed-off-by: Bao Haojun <baohaojun@gmail.com>