better logging (logs to faraday.log)
added generic rake tasks for ETL

- We can now do the following, for example: `rake legistar:structure["http://webapi.legistar.com/Help/Api/GET-v1-Client-Matters-MatterId-Sponsors",MatterSponsor]`
rename attachment files/classes for consistency
move code for district-finding into event_items rake task

- now runs automatically after loading event_items
better logging
fixes for attachments

- corrected endpoint (‘Attachments’, not ‘MatterAttachments’)
- removed old code; since we have Matters now we can use them directly instead of the hacky EventItem.where(..) stuff; and we use the generalized Legistar module now
- fix class name (Attachment->MatterAttachment in the :drop task)
- updated legistar.rb to force the setting of matter_id field on the attachment (and in general on nested items)
put log files in log directory