Basic support for async events
Use SVG for status badges in README

https://github.com/getsentry/sentry/pull/1128 can't be merged since reStructuredText is required, but at least raven-ruby can benefit from SVG badges :octopus:
Merge pull request #156 from seanlinsley/patch-1

Use SVG for status badges in README
Update Sidekiq support to 3.0 #157
Merge pull request #158 from nateberkopec/sidekiq-3

Update Sidekiq support to 3.0. Close #157.
Add async documentation to the README
Merge pull request #163 from voxmedia/async_reporting

Basic support for async events
Use e.to_s instead of e.message

Some exception have nil for it's message, and it makes it unserializable
Merge pull request #162 from huntrax11/master

Use e.to_s as fallback for e.message