Geo queries causing Posting API crash.

Hi Josh,

After doing git pull on posting api branch I'm now seeing an issue where geo queries are causing a crash. See below.

Cheers!

        00:12:08.606Z  INFO posting-api: GET /v1/postings/?start=0&count=35&filters[mandatory][contains][heading]=car&filters[optional][exact][categoryCode]=VPAR,SAPL,STOY&geo[lookup]=true&geo[min]=0&geo[max]=50000000
        >> 2015/07/24 17:12:08 "HTTP/1.1" 200 "GET" "/json/216.38.134.18" 127.0.0.1 "" 252b in 136.347us ""
        >> 
        00:12:08.613Z TRACE posting-api: request to geo coords for IP Address 127.0.0.1 completed in 5 milliseconds
        >> /Users/braddavis/WebstormProjects/htsApp/api/posting-api/lib/data/elasticsearch.js:114
        00:12:08.613Z TRACE posting-api: local IP address 127.0.0.1 will be replaced with 216.38.134.18 for request
        >> if (returnOptions.sort.asc || returnOptions.sort.desc) {
    >>                                ^
        >> TypeError: Cannot read property 'asc' of undefined
    >>     at buildQuery (/Users/braddavis/WebstormProjects/htsApp/api/posting-api/lib/data/elasticsearch.js:114:25)
    >>     at Object._onImmediate (/Users/braddavis/WebstormProjects/htsApp/api/posting-api/lib/data/elasticsearch.js:251:5)
    >>     at processImmediate [as _immediateCallback] (timers.js:345:15)
        2015-07-24T17:12:08.630-0700 [conn95] end connection 127.0.0.1:53077 (18 connections now open)
        2015-07-24T17:12:08.631-0700 [conn94] end connection 127.0.0.1:53076 (17 connections now open)
        2015-07-24T17:12:08.631-0700 [conn93] end connection 127.0.0.1:53075 (16 connections now open)
        Program node server exited with code 8

HashtagSell / posting-api

Geo queries causing Posting API crash. #81