* 3.1.x:
[ticket/14831] Rename migration and replace preg_replace() with simpler methods
[ticket/14831] Compare depends_on for migrations and remove prefixless names
[ticket/14831] Add migration for deduplicating entries and fix typo
[ticket/14831] Add method for getting valid migration name
[ticket/14831] Fall back to possible migration names instead of adding prefix
[ticket/14831] Make sure migrations always start with backslash
[ticket/14831] Make sure migrations always start with backslash
* marc1706/ticket/14831:
[ticket/14831] Rename migration and replace preg_replace() with simpler methods
[ticket/14831] Compare depends_on for migrations and remove prefixless names
[ticket/14831] Add migration for deduplicating entries and fix typo
[ticket/14831] Add method for getting valid migration name
[ticket/14831] Fall back to possible migration names instead of adding prefix
[ticket/14831] Make sure migrations always start with backslash
* 3.1.x:
[ticket/14831] Optimize code construction
[ticket/14831] Add more tests against UCP modules
[ticket/14831] Add more tests, better name for $e placeholder
[ticket/14831] Do not throw exception on the module existence checking
[ticket/14831] Fix module migrator tool
Instead of just adding the backslash as prefix if needed, this will take care
of falling back to any possible migration with or without backslash no matter
how the mgiration was saved in the database or called in the migrations file.
This will result in a more robust migrator in regards to naming the migrations
and previously run migrations.
PHPBB3-14831
The migration system expects every migration to start with a backslash.
If depends on definitions do not supply that leading backslash, we should
make sure it's added manually before calling the depends on migration.
PHPBB3-14831
Because of the new way, schema update steps are handled, the already
misleading progress bar was even more misleading. This should fix it.
PHPBB3-14742
