Immutable and Mutable instances properly respond to attribute names
Point bundler to use rubygems.org
readme.md fix and code highlight
oops, english fail
`respond_to?` responds to Object instance methods
Merge pull request #6 from artemeff/patch-1

readme.md fix and code highlight
Merge pull request #5 from ronny/rubygems-source-fix

Point bundler to use rubygems.org
Merge pull request #4 from ronny/respond-to

Immutable and Mutable instances properly respond to attribute names