Raindrops 0.2.0 - raining penguins!

For servers running Unicorn 0.98.0 (and derivative servers)
under Linux, :listeners no longer needs to be passed explicitly
when configuring the Rack middleware.

Some small documentation updates and cleanups, too.

Raindrops is a real time stats package to show statistics for Rack HTTP
servers. It is designed for preforking servers such as Rainbows! and
Unicorn, but should support any Rack HTTP server under Ruby 1.9, 1.8 and
possibly Rubinius (untested) on platforms supporting POSIX shared memory
and compiled with GCC (for atomic builtins).

Changes:

For servers running Unicorn 0.98.0 (and derivative servers)
under Linux, :listeners no longer needs to be passed explicitly
when configuring the Rack middleware.

Some small documentation updates and cleanups, too.