Fix whitespace/indentation
Allow filename prefix to be specified as an option
Update dependencies
Freeze version of rubyzip gem

rubyzip's 1.0.0 was a major release which broke backwards compatibility (https://github.com/rubyzip/rubyzip/issues/90)
This commit freezes the version of rubyzip until roo is compatible (https://github.com/Empact/roo/pull/65)