docs(item): add use cases of ion-item
docs(item): add use cases of ion-item

Closes #294

driftyco/ionic,TillaTheHun0/ionic,joshesp/ionic,alan-agius4/ionic,AbraaoAlves/ionic,driftyco/ionic,joshesp/ionic,manucorporat/ionic,janglednerves/ionic,dennybiasiolli/ionic,alan-agius4/ionic,alan-agius4/ionic,jhlee8804/ionic,jarrodkoch/ionic,jarrodkoch/ionic,TillaTheHun0/ionic,AbraaoAlves/ionic,cambronjay/ionic,cambronjay/ionic,AbraaoAlves/ionic,jhlee8804/ionic,joshesp/ionic,driftyco/ionic,manucorporat/ionic,manucorporat/ionic,jhlee8804/ionic,cambronjay/ionic,alan-agius4/ionic,dennybiasiolli/ionic,AbraaoAlves/ionic,alan-agius4/ionic,janglednerves/ionic,dennybiasiolli/ionic,driftyco/ionic,AbraaoAlves/ionic,cambronjay/ionic,TillaTheHun0/ionic,cambronjay/ionic,driftyco/ionic,manucorporat/ionic,janglednerves/ionic,jhlee8804/ionic,TillaTheHun0/ionic,jarrodkoch/ionic,jhlee8804/ionic,janglednerves/ionic,alan-agius4/ionic,dennybiasiolli/ionic,manucorporat/ionic,dennybiasiolli/ionic,janglednerves/ionic,jarrodkoch/ionic,jarrodkoch/ionic,brianespinosa/ionic2-sass,joshesp/ionic