Merge branch 'jn/scripts-updates'

* jn/scripts-updates:
remove #!interpreter line from shell libraries
test: replace shebangs with descriptions in shell libraries
test: make FILEMODE a lazy prereq
contrib: remove git-p4import
mark contributed hooks executable
mark perl test scripts executable
mark Windows build scripts executable

diff --cc contrib/completion/git-completion.bash
Simple merge

diff --cc t/lib-read-tree.sh
Simple merge

diff --cc t/test-lib.sh
Simple merge