account for bw obs. change in tor 0.2.5.11
atlas should take change 'Increase period over which bandwidth observations are aggregated' into acount and maybe connect the dots with lines as it did before?
from the tor 0.2.5.11 changelog:
o Minor bugfixes (statistics): - Increase period over which bandwidth observations are aggregated from 15 minutes to 4 hours. Fixes bug 13988; bugfix on 0.0.8pre1.