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.
Merge pull request #77 from sujeetsr/issue#59_humanize_file_size

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