Load environment for deploy task

This provides an alternative mechanism to the currently supported
environment variables to set options such as API key, and also allows
setting other options through the standard `config/bugsnag.yml` file
that were not previously available, i.e. endpoint and proxy.
Load the env if there is no api_key
Move HTTP request onto its own thread

This avoids blocking app progress
Fix jruby specs
Wait for thread to finish
Merge pull request #109 from ggilder/load-environment-for-deploy-task

Load environment for deploy task
Revert "Merge pull request #109 from ggilder/load-environment-for-deploy-task"

This reverts commit d2bca8c3e3ca5b04650e3fca669dda13f6cd50ca, reversing
changes made to 8da9ef1581c30bf8724298bd4924bc40ffd39fea.
Bump version
Fix rspec 3 error with jruby
Merge pull request #117 from dtaniwaki/fix-jruby-rspec3-error

Fix rspec 3 error with jruby
Add job detail for delayed_job
Fix for delayed_job loading
Merge pull request #114 from dtaniwaki/fix-for-delayed-job-loading

Fix for delayed_job loading
Merge pull request #113 from dtaniwaki/add-job-detail-for-delayed-job

Add job detail for delayed_job
2.1.0
Ignore exception if its ancestor is an ignored class.

When I add an ignored class, my expectation is that all subclasses
will be equally ignored. This makes it easy, for example, to ignore
all 4xx code HTTP response exceptions by specifying one generic
superclass.
Merge pull request #118 from ecin/ignore-ancestor-chain

Ignore exception if its ancestor is an ignored class.
Add note about how to handle custom errors in Sinatra

The custom error handlers halt execution, so the error will not reach
Bugsnag.
Fix reference in readme
Merge pull request #122 from RKushnir/patch-1

Fix reference in readme