Merge branch '3.1.x' into 3.2.x
* 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
Merge pull request #4492 from marc1706/ticket/14831
[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