add option to abandon chef run if blocked by another for too long
add command line option to client
add command line option to solo
convert cli argument to int, tidy exception message
update CHANGELOG and DOC_CHANGES
Merge branch 'master' into CHEF-5074

Conflicts:
	CHANGELOG.md
	DOC_CHANGES.md
Merge branch 'CHEF-5074'
document config option for runlock timeout