Fixes #72

Save disk sizes in KB in the disk model. Update the retrieval code for disks
and shares to consistantly save and return numbers in KB.
Change the size input scale to KB by default.
Modify to make default size scale to KB.
Merge pull request #76 from Mchakravartula/issue#59_humanize_size

Issue#59 humanize size
Merge pull request #74 from schakrava/issue#72_disk_sizes

Fixes #72
Humanize file sizes in disks table and shares table and usage.

Multuply file sizes by 1024 in disks table and shares table since
backend returns size in KB.
Convert sizes appropriately and use humanize to display share size in
the usage pie chart.
Remove Qgroup model and make the qgroup as a charfield of share model. Create a
new datastore.in and initial south migration file.
Fixes #36

Update the API view code to not use the deleted Qgroup model.
Merge branch 'issue#36_broken_constraint' of https://github.com/schakrava/rockstor-core into schakrava-issue#36_broken_constraint

Conflicts:
	src/rockstor/storageadmin/views/share.py
Merge pull request #77 from sujeetsr/issue#59_humanize_file_size

Humanize file sizes in disks table and shares table and usage.