MultiRepos: fix trac-svn-hook doc and some bits for Cygwin support (enables the script to be called by Cygwin's bash on Windows)
MultiRepos: fix trac-svn-hook doc and some bits for Cygwin support (enables the script to be called by Cygwin's bash on Windows)

git-svn-id: 724832444bcc56d647a9134c92586fee9d70f226@8097 af82e41b-90c4-0310-8c96-b1721e28e2e2

jun66j5/trac-ja,netjunki/trac-Pygit2,walty8/trac,jun66j5/trac-ja,netjunki/trac-Pygit2,walty8/trac,jun66j5/trac-ja,netjunki/trac-Pygit2,walty8/trac,walty8/trac,jun66j5/trac-ja