Support image mime types

This adds another specific route for image/* mime types
Maybe could be unified a bit with the multipart handling
in that code section. Creating a parser in the user code
depends heavily on the .emit('end') sequence if it works
or not...
Add content type image/png test case
Fixed: error parsing body of 204 response
for node, if no cookies given, do not set the Cookie header
replaced host to hostname
closes #404 make .agent chainable
Merge pull request #406 from kof/master

Make Request.prototype.agent chainable
Merge pull request #300 from nebulade/master

Support image mime types
Upgrade cookiejar dependency
Stop testing 0.8.x to keep travis happy
Release 0.18.1
Adds a try-catch to handle parse errors in client.
ensure not running default parser when user has defined one
inc version
Merge pull request #422 from kof/issue-421

ensure not running default parser when user has defined one
handle parser errors properly
release 0.18.2 history notes
Merge pull request #386 from prasunsultania/master

Use hostname instead of host when setting cookies
Merge pull request #323 from DveMac/master

Don't parse empty response bodies
Merge pull request #382 from undoZen/remove-empty-cookie-header

Only send cookie header if there is a cookie value