make GeoPoint parsable in lat/lon json format
add more combine functions and rename PLAIN to REPLACE
rename 'total' to 'sum', both enum and for query
Add offset to decay function score

Docs within the offset will be scored with 1.0, decay only starts after
offset is reached.
rename scale_weight -> decay
rename reference -> origin
format code
add builders for nicer java api

Closes #3533
add additional method for setting combine mode with CombineFunction parameter