Added ability to delay Rollbar.process_payload with Sidekiq

As error reporting can be slow, this adds ability to asynchronously send error details to Rollbar.
Fix specs with Ruby 1.8
Merge pull request #46 from jeremyvdw/master

Added ability to delay Rollbar.process_payload with Sidekiq
Add instructions to use Sidekiq for asynchronous reporting
Merge pull request #47 from fabsays/master

Add instructions to use Sidekiq for asynchronous reporting
add @jeremyvdw and @fabsays to THANKS
bump to 0.10.5, update changelog
Add ability to report form validation errors
We need to avoid database cleaner 1.1 due to https://github.com/bmabey/database_cleaner/issues/224
Fix for #32
up version and update THANKS
Merge branch 'master' of github.com:fabsays/rollbar-gem into fabsays-master
up version
add MIT license to gemspec
update changelog: no need for separate release; 0.10.7 has not been pushed to rubygems yet.
Better handling of internal errors.

1. Attempt to report internal errors as exceptions to Rollbar. Internal errors are reported in the normally-configured project (for examination by the project developers) and flagged as internal (for examination by Rollbar staff).
2. if reporting the internal error fails, send a mostly-static failsafe response. The failsafe is also reported in the project context, and flagged as both "internal" and "failsafe".
3. if the failsafe fails, log an error.

Additionally: all logger calls in lib/rollbar.rb are now done via wrappers (`log_error`, etc.) that catch exceptions in such calls.
Fix NoMethodError when backtrace contains a line that doesn't match our regex. Fixes #51
bump to version 0.10.8, update changelog
Fix error if ActiveRecord isn't present.

This solves a uninitialized constant error when using outside of Rails.
Merge pull request #54 from awmichel/fix-sinatra-error

Fix Uninitialized Constant Error with Sinatra