Fix similar for DefaultDict
Add test for similar(DefaultDict)
Merge pull request #30 from wsliang/dd_similar

Fix similar for DefaultDict
Fix broken tests
Merge pull request #32 from wsliang/fix_test_trie

Fix broken test
Revert "Remove unused code"

This reverts commit a7ddafbe1d74ce25ef0168e7f5746f03ad084b80, and
updates the TODO comment to remove the code if/when Julia v0.3
is required.