`docker-entrypoint.sh`:
- update `docker_process_init_files` to take in a list of file
- update `docker_process_sql` to take sql input on stdin to maintain compatibility with `mysql` (and prevent us from loading an entire `.sql` file into memory)
- move any code that was outside a function to `_main` or other functions
- use `local` variables in functions to limit scope
- move current `docker_create_db_directories` logic to `docker_init_database_dir`
- new docker_create_db_directories that just creates and chowns directories
- move `PASSFILE` to be in memory only so that we don't accidentally not clean it up
- move `FLUSH PRIVILEGES` to fix https://github.com/docker-library/mysql/pull/549
update.sh:
- add back `DELETE` statement for 5.5 and 5.6
- swap some template strings to single quotes to make it easier to read
- swap `sed` to use ! for delimter
- use one loop rather than two
Joe Ferguson