Merge pull request #73 from k-yamada/master

Allow Raven to initialize with an server_name variable
Fail gracefully when a transport is unable to send data
Change Sentry 403 error to a logged event instead
Merge pull request #75 from seomoz/handle_error_403

Change Sentry 403 error to a logged event instead
Properly clear user/tags/extra context after request.
Merge pull request #76 from DouweM/properly-clear-context

Properly clear user/tags/extra context after request.
0.4.5
Update client.rb

Fix invalid call to logger in raven client
Merge pull request #79 from veilleperso/master

Fix invalid call to logger