[excon] pass client side cert information to excon
Make Headers#fetch case-insensitive

Matches the behavior of `[]` and `[]=` methods. Also accepts symbols:

    headers.fetch(:content_type)
allow custom env keys in an embedded hash
tomdoc some methods
Avoid using buggy version of Excon

Breaks with combination of proxy + HTTPS

geemus/excon#291
fix Env#in_member_set? on 1.8.7.  make Env#member_set a class method
Merge pull request #311 from lostisland/custom-env-keys

allow custom env keys in an embedded hash
Autoloads by default, but makes it easy to disable.
don't require things twice now that autoload is default.

removes require lines added by some jackass in
d0437a1cb42f74b865bcf5fa6111d77b72a88688
autoload instrumentation too
Merge pull request #312 from lostisland/autoload-by-default

Autoloads by default, but makes it easy to disable.
Options#fetch should not return the default for false or nil values.
bring #build_url back yall

https://github.com/intridea/oauth2/issues/144
not testing build_url anywhere, update test names
add a few build_exclusive_url and build_url tests
Merge pull request #288 from ehowe/master

[excon] pass client side cert information to excon
Merge branch 'master' of https://github.com/benburkert/faraday into default-fetch-fixes
stop shadowing Faraday::Options
make Faraday::Options#fetch more like Hash#fetch
Lock mime-types to ~> 1.25 on Ruby 1.8