Add Gemfile and remove versions from gemspec
Use rake-compiler for gem tasks
Move functional tests to specs
Move compatibility tests to specs
Reinstate valgrind task
Run specs as the default task
Travis CI configuration
Fix regexp for Ruby 1.8.7

There is no hexadecimal character class.
Describe compatibility with SecureRandom
Add benchmarks to Travis CI builds
Run benchmarks for only a few Ruby versions
Merge pull request #1 from cbandy/update-tooling

Update tooling