Add cron tasks to manage audit_atom table
Added configurable options to dump daily audit reports and prune older logs from the table with or without dumping them to a file first.
Added rotate method to Ilios_Logger which can be used to rotate and compress log files
Resolves #424
Merge pull request #556 from jrjohnson/424-auditdump

Add cron tasks to manage audit_atom table  #424
Initial CONTRIBUTING.md file

Probably needs some work over time, but its a start.
Fix behat link in CONTRIBUTING.md
Update CONTRIBUTING.md with coding standards
Merge pull request #557 from jrjohnson/468-addcontributing

Initial CONTRIBUTING.md file