We're not interested in minor versions right now

We're only interested in major backwards compatability
for the moment. It's too much of an issue to keep up
with minor version bugs in MRI.
Focusing on latest of these minor versions.
Merge pull request #142 from hamstergem/removing-old-2-ruby-support

We're not interested in minor versions right now
Cutting another rc release.
Applying some new badges

These badges are a little more helpful, when they work.
Merge pull request #149 from hamstergem/new-badges

Applying some new badges
Woops, didn't catch these in the rename [no-ci]
Optimize Hash#merge and Set#union by using Trie#bulk_put

Implemented Trie#bulk_put which performs several puts at once without
creating new temporary Trie objects on every put operation. This method
is then used in Hash#merge and Set#union in order to improve their
performance.
WIP improve Trie#bulk_put performance by dividing to buckets according to index
WIP add bulk_put! for performance
WIP more attempts at performance of bulk_put!