Exclude is the correct term to use when removing paths from the
list of checked items. Ignore as a term was a poor choise to begin
with. XML file reading still recognizes and reads the 'ignore'
element but writes 'exclude' element.
Ticket: #2995 (GUI: Rename ignore-feature to exclude-feature)
Add applying of filtering into list of files to check if we have
an active project file. Filtering is quite much similar to the
filtering in CLI.
If we have directory filter ("gui/") then we check all paths if
they contain "gui" part. In practice we search for string "/gui"
from the paths. If we have filename filtering
("gui/projectfile.cpp") then we check if any of the paths end
with that.
I accidentally committed two new files with filenames starting
with capital letters from Windows machine. The Linux build
breakage was fixed by fixing the include lines. But the correct
fix is to fix filenames as we are using all lower letter filenames
in this project.
