Add include/includes #45
Description
See discussion at #39
One should be able to apply include rules (in addition to exclude rules) to the files being considered.
Namely:
no include, no exclude => all files in the source sets should be considered
include(s) => only files matching the includes should be considered
exclude(s) => all files except those matching the excludes
include(s) + excludes(s) => only files matching the includes but not matching the excludes