Extended copy_files part of the control file

- Added ID for easier referencing from outside
Renamed one function

- in fact, fixing a typo
Prepared for skipping unwaqnted features defined in control file

- features will be referenced by ID defined in control file
Control file ID changed to more understandable one

- will be used as "ignore_feature(s)=$ID,$ID,..."
Added feature that returns ignored features got from Linuxrc commandline
Added test into subdirs
Added changes file entry
Finished feature "ignored_features=$x" for Linuxrc commandline
Added Makefile.am for tests
Added support for checking for undefined feature
Fixed according to comments
Added missing dependency
Updated gitignore
Merge pull request #1 from mchf/ignored_features_add

Updated gitignore
Merge pull request #79 from kobliha/ignored_features_fate314982

Added possibility to ignore some installation features (on user request)