Defined Vifm with various versions depending on platform (0.7.3a on Darwin, 0.7.4b on Linux and 0.6.3 on FreeBSD)

Signed-off-by: Daniel (dmilith) Dettlaff <dmilith@verknowsys.com>
Remove +x from launcher.cc

Signed-off-by: Daniel (dmilith) Dettlaff <dmilith@verknowsys.com>
Added libmagic-dev to list of required packaged on Debian. (added to README)

Signed-off-by: Daniel (dmilith) Dettlaff <dmilith@verknowsys.com>