update addon-sdk submodule to tip of stabilization branch (stabilizing to 1.14 release)
Revert "use our own version of io/file to work around bug 836061" now that we've updated SDK to stabilization tip, which contains fix

This reverts commit 51e620859cd28151d25ca81f74c186acc99124de.
Merge pull request #298 from mykmelez/update-sdk

update addon-sdk submodule to 1.14 stabilization tip