adapted gemspec and container.rb to support Rails 4
rubyzip "~>0.9.1" -> "~> 1.0"
Choosing the more conservative route for Rails 4 support

Also, fixed Rakefile. Gem dependencies should be specified there.
gemspec is auto-generated.
Merge branch 'gdelfino'

Conflicts:
	Gemfile
	rodf.gemspec
Ensure that the rubyzip dependency update will survive gem repackaging
Bumps up version number for publishing