systemd socket activation
after socket activation remove LISTEN_FDS and LISTEN_PID environment variables
Update README for shorter gem description

Hoe parses out the `## Description` section for use in the gemspec description,
which at present is very large and uses markdown that the gemspec / rubygems
doesn't care about.

This commit replaces the description with an abbreviated version, and puts the
full description below a new header "built for speed and concurrency"
fix: stop leaking sockets on restart (affects ruby 1.9.3 or before)
Update puma-manager.conf

Added quotes to /etc/puma.conf
It is 2013 [ci skip]
Merge pull request #269 from joneslee85/patch-8

It is 2013 [ci skip]
Merge pull request #267 from baruchlubinsky/master

Fix an error in puma-manager.conf
Merge pull request #259 from sugitak/fix_socket_leak

fix: stop leaking sockets on restart (affects ruby 1.9.3 or before)
Merge pull request #247 from catsby/update_gem_description

Shorten the gemspec description
Merge pull request #231 from urbaniak/socket-activation

Socket activation
Error out early if there is no app configured
Ignore errors on the cross-thread pipe. Fixes #246

The @notify pipe is used to give commands to the server running in
another thread. The server might be shutting down at the moment we send
it a command, thus it might have closed @notify, so we ignore errors.
Handle errors from the server better
Handle all read exceptions properly. Fixes #252
Fix typo
Handle ConnectionError rather than the lowlevel exceptions
Deal with pipes closing while stopping. Fixes #270

The bug was that the SIGCHLD handler would fire after the ensure block
that closed the pipe. We can just ignore write errors on that pipe.
use configured rackup file or fall back to the default config.ru in the app_configured? check
Merge pull request #271 from Arie/master

app_configured? check should fall back to default rackup file