First commit in feature branch for mutable shield
with eval in 'single quotes'.
Working variant of the mutable 'shield' function
with evaluating exec string in 'single quotes'.
Merge branch 'feature-shield-eval-single-quote'
Clean the code.
More clean code - removed subfunction in the 'shield' function.
Yet another clean code: remove the 'remark-insert' function.
Modify function the 'echo_remark' for excluding function 'o_name'.
Exclude function 'o_name'.
Clean the code:
- remove prev. version of the function 'shield', the function 'o_name';
- reordering functions: move the 'shield' function at the bottom
   of function list and more small updates.
Next changes were made:
- tmpbuf is now crated in a subdirectory 'folding_{XXX}' of /tmp catalog;
- mk config dir for dev moved from ю./my.grub.dir to ./grub.dir,
    required changes are made in the programs;
- updated README.md: added description of the expansion of the list
    of supported operating systems.