Update .gitignore

Commit 353719a2ddec4d6a8458ee42af37514fedbd80bf adds gmarshal_funcs.c, gmarshal_funcs.h.

Commit a223b6b426c1897977b987d0ddce434afba604da adds /bin/, barnowl, tester and removes barnowl.bin, tester.bin.

Automake 1.13 (which enables the parallel testsuite harness by default) adds runtests.sh.log, runtests.sh.trs, test-driver, test-suite.log.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>