gitweb: add notfound template

Add message to test output if a test is aborted due to a timeout. Without this an aborted test could produce an empty .err file so the diff looks like as if all lines of the .out files are just missing for some unknown reason.

Fix issue 653: symlinks checkout failure on non-supporting platforms

test-oldcgi: replace shebangs with explicit python calls to help pysh.

test-issue352: skip tests if platform does not support EOL in paths.

hghave: detect support for EOL in paths.

test-git-import: fake executable permissions.

hghave: detect executable permission availability.

test-clone-failure: fake output upon fifo unavailabity

hghave: detect FIFO availability