Flesh out directory structure

According to the proposal made in e-mail:

/ - this is the Git repo
/shrapnel/ - Django package
/shrapnel/scheduling/ - scheduling and time parsing; should probably include the Followup model?
/shrapnel/email/ - email reception
/shrapnel/users/ - user settings
/cron_scripts - stuff that would go in cron_scripts for deploying on Scripts (i.e. crontab)
/mail_scripts - stuff that would go in mail_scripts for deploying on Scripts (i.e. procmailrc)
/web_scripts - stuff that would go in web_scripts for deploying on Scripts (i.e. fcgi)
Fix file path settings