Fixed plural form for AssetCategory model
ralph_device_id gets cleaned when device linked to it gets deleted.
Merge pull request #49 from xor-xor/t1376

ralph_device_id gets cleaned when device linked to it gets deleted.
Added partial and exact searches to assets.
Merge pull request #50 from xor-xor/t1229

Added partial and exact searches to assets.
Merge pull request #47 from deejay1/fixes

Fixed plural form for AssetCategory model
api_ralph - minor fixes