Support Optional First/Last & More Characters in Range Endpoints

New Features:

• First and last endpoints are now optional and nil if missing
• Allow more characters in range endpoints, including .

Fix: Allow Requiring of Middleware Directly

Bug Fixes:

• Allow apps to require 'http_range/middleware/accept_ranges' directly.

Add Rack Middleware

New Features:

• Added HTTPRange::Middleware::AcceptRanges middleware for quickly parsing Range headers in a Rack application.

Bug Fixes:

• Passing a nil value to HTTPRange.parse() now correctly raises HTTPRange::MalformedRangeHeaderError instead of a native Ruby exception.

Initial Release

Just a Ruby method interface: HTTPRange.parse(string).