add intrinsic rule(s) for testing processors kinds support

[szaghi]

The modern standards provide many goodies about kindness, but processors (compilers) are free with respect how to implement them, e.g. Intel does not support iso_ 10646 character kind whereas GNU does, thus we have

print*, selected_char_kind('ascii')     ! => 1 for both GNU and Intel
print*, selected_char_kind('iso_10646') ! => 4 for GNU and => -1 for Intel

It could be very helpful if FoBiS provides an intrinsic rule(s) to test the compiler supported kindness, e.g.

FoBiS.py rule -support_char_kind 'iso_10646' # echo yes or not
FoBiS.py rule -support_real_kind '(33,4931)' # echo yes or not

Essentially, FoBiS will automatically create/compile/run/remove a tiny program for the introspective test like the following

program fobis_rule_selected_char_kind
print*, selected_char_kind(#macro_passed_by_fobis)
endprogram fobis_rule_selected_char_kind

program fobis_rule_selected_int_kind
print*, selected_int_kind(#macro_passed_by_fobis)
endprogram fobis_rule_selected_int_kind

program fobis_rule_selected_real_kind
print*, selected_real_kind(#macro_passed_by_fobis)
endprogram fobis_rule_selected_real_kind

Upon execution, FoBiS intercept the output and if it is >0 the compiler is assumed to support the queried kind.

[szaghi]

Added in new 2.2.4.

It would be nice to add a new option to exclude files from being parsed for doctesting, but still included for compilation...

[szaghi]

Added also option to exclude files from doctesting. Works great.