searches use scrolling for much win

[dmfenton]

Instead of requesting everything at once, this pages and uses a search type of scan to avoid any scoring

Benefits:

• Process no longer has to hold entire searches in memory at once
• much faster for large requests

See: https://www.elastic.co/guide/en/elasticsearch/guide/current/scan-scroll.html

[dmfenton]

Need to do some more profiling and optimizing

[dmfenton]

Tested against: 127.0.0.1:1337/agol/arcgis/780a3f7babe74f18aaebdd42dbe4a911/FeatureServer/0

Status Quo: 445,210 ms :turtle:

Batch size	Response time (ms)
100	50,918
200	25,450
250	25,613
500	26,915
750	27,360
1,000	28,971

[chelm]

@dmfenton those response times rock. So will you rebase this with master? Then i'll merge it

[dmfenton]

Rolled everything into a 0.1.1 since we haven't released anything else.