Add support for batch processing in actions

When executing a queryset, in case of most actions (eg: where, filter
etc), it is possible and more efficient to run the processor on a merged
entry. This results in a single iteration for an action type.

It will be used in implementations of filter/where.

Signed-off-by: Rohan Jain <crodjer@gmail.com>
Add a utility to filter arrays

 - Filter definition has been borrowed from underscore
 - Also add a function to wrap array into a object for testing

Signed-off-by: Rohan Jain <crodjer@gmail.com>
Support for filtering on query set data

Add add chainable filtering over query set. Multiple filters are
combined into one. This is a simpler but more powerful api than a
typical SQL based ORM `WHERE` clause. Somthing simplere but with
stripped down features is upcoming.

Signed-off-by: Rohan Jain <crodjer@gmail.com>