Move graph lag compensation to _graph.push method.
Include a lag limit to avoid issues following suspend.
Remove the lag, and make the lag_cycles visible to update_graph,
just in case we decide to make use of it.
Multiple inserts should not take too many cycles, thanks tych0.
Don't crash on exceptions from hooks
this_screen_border other_screen_border and urgent_border defined twice
Also remove duplicate urgent_alert_method

Thanks @WnP for pointing this out.
Fix typo in docs
Don't crash on moving to a nonexistent group

Fixes #360
Remove unused (and confusing) arguments
Log full exception from cmd_function() crashes
divide only if total isn't 0 in cpugraph

Closes #367
ellipsize text in tasklist widget

Closes #366
Fixes problems with focus when clicking windows

Conflicts:
	libqtile/manager.py

Closes #365

@tych0: small change to remove cmd_dummy and just use a noop function.
Fix some typos in the docs
CHANGELOG for 0.7
Have Slice proxy cmd_ calls to the fallback layout.

I use Slice to create a fixed with browser window with a Stack of (depending
on screen width) one or more stacks next to it. This changeset helps getting
shuffle and split commands to the Stack.

Closes #369
Ensure WithdrawState windows stay unmapped on restart
Obey min/max/inc width/height hints
Don't log events in qtile.ignoreEvents to debug
General cleanup of layouts for naming consistency

All windows are named "client"
All window lists are named "self.clients"
All info() methods return an item called "clients"

Also removed some useless imports