Use HTTP::Resonse::Status::REASONS table

`HTTP::Response::STATUS_CODES` and `HTTP::Response::SYMBOL_TO_STATUS_CODE` were
deprecated in the HTTP Gem and will be removed in one of upcoming releases.
Merge pull request #151 from ixti/refactoring/http-gem-master-compat

Use HTTP::Resonse::Status::REASONS table
Remove --default-path from .rspec
Use Timers 3.0.0 API
Test on 2.1.2
case-insensitivity for header field names

while testing [angelo](http://github.com/kenichi/angelo) on
heroku, i discovered that heroku's router is downcasing request
header keys. this is valid according to:

http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2

this change should make all access to request header keys
insensitive, though probably not in a very performant way.
slightly more performant
Merge pull request #152 from kenichi/case_header_keys

case-insensitivity for header field names
openssl sometimes fires Errno::ECONNRESET as an error
Merge pull request #155 from czaks/sslerror

openssl sometimes fires Errno::ECONNRESET as an error
HTTPS: EPIPE can happen here as well
Merge pull request #156 from czaks/master

HTTPS: EPIPE can happen here as well
HTTPS: ETIMEDOUT, EHOSTUNREACH can happen here as well
Merge pull request #157 from czaks/master

HTTPS: ETIMEDOUT, EHOSTUNREACH can happen here as well
remove optimize function

it isn't used and it doesn't work
remove optimize from http server
remove optimize from https server
Merge pull request #158 from czaks/remove-optimize

Remove optimize function
Fixes 404 error in roundtrip example
Merge pull request #160 from jgrowl/master

Fixes 404 error in roundtrip example