Specify database name during database import

Mysql needs a database name to be specified if it isn't already so in the SQL file being imported
Refactor handling of initial database setup

Our naming convention was a little weird before and various scripts for mysql were kind of hidden all over. This does a few things...

* Establishes an init.sql file that creates our default WordPress database and an external user to be used by the local machine for non SSH tunnel connections to mysql. This init.sql file will be where any SQL specific to this vagrant repo will be stored.

* Establishes the concept of an init-custom.sql file that will be used on individual setups to control the databases and users created during a vagrant up. This file must be created by the user, but a sample is included in init-custom.sql.sample

* Ditches create-dbs.sql.sample and default-dbs.sql in favor of this new naming convention
* Alters .gitignore in favor of the new naming convention
* Reorgs the order of things in provision.sh to account for the new naming convention
Additional readme for database/data directory
Add commenting to import-sql.sh
Clarify readme for mysqldump files
Cheap check for database before importing

Look for an existing database data directory before trying to import the mysqldump file. This is pretty cheap and may not work as a long term solution, but we'll see.

Addresses Issue #9
Do a true check on existing tables before importing

Rather than looking for a directory, which I could see causing issues in a few places, we use SHOW DATABASES LIKE from the command line to see if the current database already exists.
Improved check for existing database before import

Now this is pretty boss.

Check for tables on each database before attempting to import.
* If a database does not exist, an error is thrown that we catch and add more info to
* If a database does exist, but has tables, we skip it because we more than likely imported already
* If a database does exist, but has no tables, we do the import from database/backups

Sweeeet.