Use RubyGems over SSL
Replace Jeweler with Bundler
Convert tests to RSpec
Switch from RCov to SimpleCov for Ruby 1.9+
Whitespace
Add test for invalid `seek` option
Drop support for Ruby 1.8
Extract encoding support checks into helper methods
Support reading both UTF-8 and raw from Gzip streams
Only instantiate a BlockState when necessary

This fixes usage with $stdin.
Add test for filtering from a pipe
Merge branch 'pipes'

* pipes:
  Add test for filtering from a pipe
  Only instantiate a BlockState when necessary

Closes #1
Bump version