Add optional disable flag for namespace locking

Add documentation for override environment variables in README

If DISABLE_NAMESPACE_LOCK is enabled ( == 1), don't complete the logic
to set the lock and fail over if lock exists.
Merge branch 'lockfile' into optional_namespace
Merge branch 'lockfile' into optional_namespace

Conflicts:
	src/marquise.c
rm whitespace creep
Merge pull request #26 from anchor/optional_namespace

Add optional disable flag for namespace locking
Merge pull request #27 from anchor/lockfile

(cleanup) Merge lockfile branch into master