#28 - port FCM (and test suite) to Subversion 1.8

This addresses part of #28. It ports the existing test suite to run OK with Subversion 1.8.1. The exception is the `add-add` test case in `fcm conflicts` which is broken due to a since-fixed 1.8 bug.

The next step after this is to add more tests in 1.6 and 1.8 - in particular, `fcm loc-layout`, and more merge tests.

It looks like the sort order for status, diff, and update changes further in 1.8.x, so we may have to alter the test suite again when a later 1.8 release comes around.

@matthewrmshin, please review.