engine: Use external echo binary when possible
engine: Use external echo binary when possible

Some shell buil-in echo (dash on Debian, for example)
do not support coloring (-e option)

Signed-off-by: Dmitry Fleytman <a8cf97adadec4e1b734a39bc5aea71b5741cfca1@daynix.com>

daynix/rebuild,daynix/rebuild,rbld/rebuild,rbld/rebuild,daynix/rebuild,rbld/rebuild