Ensure DummyHandler instances are different.

Before this change, `a == b` would be true, which would cause the
tests not to fail if the wrong handler was returned.
Support prefix and exact route at same path

This is sometimes needed when the landing page for a thing is handled by
a separate app from the rest of the thing.

This has involved changing the triemux to store 2 tries, one for the
prefix routes, and one for the exact routes.  This also now uses the
GetLongestPrefix method to do the lookup in the prefixTrie, which means
that each path lookup now involves at most 2 trie lookups.
Setup travis to test against 1.0 and 1.1
Merge pull request #1 from alext/same_path_prefix_and_exact_route

Support prefix and exact route at same path