Fix #1339 Force backslashes with path.posix
Fix #1339 Force backslashes with path.posix

Index's addByPath function does not accept backslashes. To ensure
that forward slashes are used, path.posix is used to join paths
together with a forward slash in a platform independent way.

Signed-off-by: Remy Suen <553f7e7fc51e9ff47ae89d5a0ebd06651241b998@gmail.com>

jmurzy/nodegit,nodegit/nodegit,jmurzy/nodegit,nodegit/nodegit,jmurzy/nodegit,nodegit/nodegit,nodegit/nodegit,jmurzy/nodegit,jmurzy/nodegit,nodegit/nodegit