add correct RTLD constants at compile time
update Gemfile and .travis
Update .travis.yml
add bundler build byproducts to gitignore
update development dependencies
fix .travis.yml assumption
update MRI version
remove Rakefile cruft
add dev group to Gemfile
Merge pull request #329 from tduehr/rtld_mlock

Correct and update Gemfile. Additional testing on travis.