Changed routing diagnosis socket state from enum to int so that they can
be bitwiseor'ed together.

Review: https://reviews.apache.org/r/26236
Included a missing header file in src/Makefile.am.
Fixed the flaky SlaveRecoverTest.MultipleSlaves.

Review: https://reviews.apache.org/r/26243
Switched path::join() to be variadic

Review: https://reviews.apache.org/r/25818
Added functionality to create SVN based diffs of arbitrary strings.

See summary.

Note that this hard codes the location of the subversion and Apache Portable Runtime (APR) headers.

Review: https://reviews.apache.org/r/24535
Added DIFF to the replicated log state storage implementation.

See summary.

Note that this hard codes the location of the subversion and Apache Portable Runtime (APR) headers.

Review: https://reviews.apache.org/r/24536
Updated metrics::Timer::stop to return elapsed time.

See summary.

Review: https://reviews.apache.org/r/24537
Add build config for svn and apr libraries