use named subroutines instead of lambdas - easier to debug...
rename argument name passed to plugin: value -> argument
we will not use ordereddict as base for FFPlugins

if FFPlugins is any kind of dict, then we cannot use more then once
given test. This is important limit :/
Now, as a base for FFPlugins, we use list :)
cache size, not result of test

we need to execute the same test on the same path with
different arguments