Change hardcoded perl path to use env

[noaxispoint]

Please look at changing the hardcoded perl path of /usr/bin/perl to using env.

For example:

#!/usr/bin/perl

to

#!/usr/bin/env perl

[EnDe]

This seams to be a valid requirement for users. Unfortunatelly "env perl" (or any other program) does not allow using additional arguments. Using arguments to the called interpreter is often used during development, makes developers live easier;)

I will add an option to the INSATALL.sh, so the user may get her/his behaviour.

Anyway, this requirement also showed me that there needs to be some clean-up about hashbang usages.

[EnDe]

Description about pros&cons of /usr/bin/env added to docs/concepts.txt, see "Using env" there. New option --useenv implemented in INSTALL.sh. Another option --usegnuenv for INSTALL.sh comming soon ...

[EnDe]

Additional option --gnuenv implemented in INSTALL.sh