just in case it attempts to sync Consumidor Final
added Cliente#consumidor_final? and not validating RUC when consumidor final
changed attributes of Item

`base` is now `base_venta`
added:
 - `(boolean)` `se_vende`
 - `(boolean)` `se_compra`
 - `(float)` `base_compra`
serialising new Item attributes
updated .label font-weight
presets
changing templates to new Item attributes
accepting new attributes
refactored to work with new item attributes
added indexes to item (and annotate)
added `type` scope to Item
querying for items based on type
updated schedule (still testing)