Merge branch '3.2.x'
* 3.2.x:
[ticket/14733] Make sure detect_algorithm() works correctly and add tests
[ticket/14733] Extend passwords driver_interface in rehashable_driver_interface
[ticket/14733] Use new interface to preserve backwards compatibility
[ticket/14733] Use default cost factor in bcrypt constructor
[ticket/14733] Support increasing hashing cost factor
Merge pull request #4405 from marc1706/ticket/14733
[ticket/14733] Support increasing hashing cost factor
* marc1706/ticket/14733:
[ticket/14733] Make sure detect_algorithm() works correctly and add tests
[ticket/14733] Extend passwords driver_interface in rehashable_driver_interface
[ticket/14733] Use new interface to preserve backwards compatibility
[ticket/14733] Use default cost factor in bcrypt constructor
[ticket/14733] Support increasing hashing cost factor
[ticket/14733] Make sure detect_algorithm() works correctly and add tests
detect_algorithm() returned array() if an algorithm prefix was more than 2
characters long. This might have been invalid for other prefixes. In order
to correctly cope with other prefixes, another check for a backslash in the
prefix definitino has been added.
This was discovered while writing the tests for the newly added interface.
