Building deb package. First attempt

makefile.linux is amended with two targets:

build-deb-package - builds deb package file 
debclean - cleans all artifacts: intermediate and final that are 
created by build-deb-package. Do not include into 'clean' target 
in the makefile as the 'clean' is called from 'build-deb-package'


The makefile targets succeed on my Ubuntu-64. The deb package
has been successfully  installed with 'sudo dpkg -i  filename.deb' 
on my box

Deb package creation tools, as described in 
https://www.debian.org/doc/manuals/maint-guide/start.en.html , 
are needed to build the targets

This is first attempt. Makefile, and the whole build procedure needs
more brain investment.
Merge branch 'master' of https://github.com/helgp/WalCommander
Merge pull request #151 from helgp/master

Building DEB package. First attempt