As you know, de facto PHP style checking is PHP CodeSniffer. This does not support progressive mode.
However, running this with grep on the command line is trivial so that you can start with errors and then take care of the warnings “gradually” at a later stage of progress.
Eclipse code integration (Screenshot and links) is also good and will allow you to do something similar, but only from the IDE.
- , IDE PHPStorm, - . , .