Allow retrieval of the totals for a given report

[dancingcactus]

should be something like this.

report.totals
>>> {'visits':{'value':12315,'friendly_name':'Visits', 'id':'visits'},'uniquevisitors':{'value':1231,'friendly_name':'Unique Visitors', 'id':'uniquevisitors'}}

[dancingcactus]

One thing to think about is who this should work with calculated metrics and such.