fix(#23): more compact message and cut too long part

[LaoshuBaby]

Close #23

[LaoshuBaby]

https://www.openstreetmap.org/changeset/173432255

looks it work well and more compact comment can let former "impossible" upload become "possible" (I guess a osm mapper who can find this tool should be able to read and understand those "v"/"n"/"w"/"r" means what)

ALso, I guess those part in simple_revert.py also have similar potential problem

simple-revert/simple_revert/simple_revert.py

Lines 331 to 335 in 22b5b17

	tags = {
	'created_by': 'simple_revert.py',
	'comment': comment or 'Reverting {0}'.format(', '.join(
	['{0} by {1}'.format(str(x), ch_users[x]) for x in changesets]))
	}