Allow configuration of shared_schemas in database.yml.  Adapt create_table to treat table creation differently depending on whether a specific schema is requested or not.  The intent here is to cater for multi-tenancy.  Loading a schema, which we'll do for each new tenant, shouldn't overwrite tables in schared schemas.  Since these shared tables are in a specific schema we can use this fact to flag the following behaviour:

1.	If the table doesn't exist, create it
2.	If it does exist and the only schema in the search path is the specified schema, go ahead and load/replace it
3.	Otherwise don't attempt to recreate it
Cleanup comments
Specify ruby verion in Gemfile
Heroku required Gemfile.lock
Change evernote gem location:
Updated gemfile
Vendored version of exiftool
Add Procfile and unicorn config for Heroku