colselect: Basic structure

Makefile to select columns from source data in main directory.
colselect: Select inner columns from source data
Generalize variable names for column selection
cossin: cossin.mk harmonized with colselect.mk
colselect: Allow to combine makefiles for source data

The aim is to allow for subsequent selection of makefiles
for column selection, data preprocessing and projection.
cossin: Allow to combine makefiles for source data

The aim is to allow for subsequent selection of makefiles
for column selection, data preprocessing and projection.
pca: Allow to combine colselect/cossin and pca
dpca: Remove obsolete dpca.mk

Dihedral principal component anaylsis (dPCA) is now
done by selecting cossin and pca as projtargets.
example: Column selection is not needed anymore
example: Larger difference in variances

This improves the ability of PCA to separate the components.
Rename variable PROJSUFFIX to SUFFIX
main: Fix determination of final suffix

Determine suffix for data that is further analysed.
main: Unused variable PROJDROPSUFFIX removed
example: Makefile improved for portability
tica: tica.mk harmonized with pca.mk