Added more detailed readme

Change-Id: Ia8a06d963c51e3ebccd778b15c12807d9a04c91b

# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
# On branch master
# Your branch is ahead of 'github/master' by 2 commits.
#   (use "git push" to publish your local commits)
#
# Changes to be committed:
#	new file:   COPYING
#	new file:   README.md
#	deleted:    README.txt
#	new file:   scripts/docker/dosek-base/README.md
#
# Untracked files:
#	README.html
#	texput.log
#	with-opt.cc
#	without-opt.cc
#
