455 script for model name changing

This script renames
* words in the code
* code files
* everything in the database by creating a new migration file
 * tables
 * columns
 * indexes
 * functions
 * words in function bodies
* factory files (appends _factory) to the filename

I only tested if the migrations can be executed. After running this script, we need to check the renames manually. It will rename more than it is supposed to. I *think* that it won't refrain renaming what needs to be renamed, but we should have an eye on that, too.
Do not use `%x` unless the command string contains backquotes.