Disk Utilization widget template and view

Placeholder view and template for disk utilization widget
Disk activity with updates

Add d3 functions to render and update activity table.
Disk utilization

Add jquery sparkline plugin
Store generated data in array for sparklines
Update smartdb model for disk utilization. Update the relevant model fields
from IntegerField to FloatField to match the values computed. Add the south
migration file for it. Add serializer for disk utilization.
Compute disk utilization information from /proc/diskstats. Add logging to the
proc retreiver.
Add API support for disk utilization statistics. Support query
parameters: limit=x returns upto x latest statistics. t1=x&t2=y returns
statistics between t1 and t2. t1 and t2 are timestamp strings deserialized from
django DateTimeField.
Update CLI to retreive disk utilization statistics.
Update setuptools_source url to get the latest setuptools for buildout to work
properly.
Merge branch 'issue#113_backend' of https://github.com/schakrava/rockstor-core into disk_utilization
Implement pagination for disk utilization stats api. This also serves as a
pilot implementation before doing the same accross the board for all smart
probes.
Modified data format

Modified sample data format to match that returned by server
Merge branch 'issue#113_backend' of https://github.com/schakrava/rockstor-core into disk_utilization
Misc fixes.
1. Increase page size to 5000 in pagination of disk stats.
2. Catch lowlevel btrfs-debug-tree exception, log and ignore while getting pool
usage.
3. give explicit timestamp for disk stats to the data is normalized.
Merge branch 'issue#113_backend' of https://github.com/schakrava/rockstor-core into disk_utilization
Remove auto_now for disk stat to help with normalization.
Migration file for disk stat auto_now change
Merge branch 'issue#113_backend' of https://github.com/schakrava/rockstor-core into disk_utilization
Disk utilization

Get data from backend
Disk Utilization

Construct array for sparklines
Display sparklines for columns
Merge pull request #147 from sujeetsr/issue#113_disk_utilization

Issue#113 disk utilization