Remove checks for longitude validity.

sanitiser/_geo.js
	-Remove the code that verified `longitude` validity, to allow
	longitude values outside of the value's real range, [-180, 180].
	elasticsearch appears to handle them gracefully, so this
	resolves #56.

sanitiser/_geo.js

@@ -1,3 +1,4 @@
+var util = require( 'util' );
 var isObject = require('is-object');
 
 
@@ -46,26 +47,25 @@ function sanitize_bbox( clean, param ) {
     return;
   }
 
-  var bbox = [];
   var bboxArr = param.split( ',' );
 
   if( Array.isArray( bboxArr ) && bboxArr.length === 4 ) {
 
-    bbox = bboxArr.filter( function( latlon, index ) {
-      latlon = parseFloat( latlon, 10 );
-      return !(lat_lon_checks[(index % 2 === 0 ? 'lon' : 'lat')].is_invalid( latlon ));
+    var bbox = bboxArr.map( function ( latlon ){
+      return parseFloat( latlon, 10 );
+    });
+    bboxArr.forEach( function( latlon, index ) {
+      if( index % 2 === 1 && check_lat.is_invalid( latlon ) ){
+        throw new Error( 'Invalid lat: ' + latlon );
+      }
     });
 
-    if( bbox.length === 4 ) {
     clean.bbox = {
       right: Math.max( bbox[0], bbox[2] ),
       top: Math.max( bbox[1], bbox[3] ),
       left: Math.min( bbox[0], bbox[2] ),
       bottom: Math.min( bbox[1], bbox[3] )
     };
-    } else {
-      throw new Error('invalid bbox');
-    }
   }
 }
 
@@ -80,13 +80,13 @@ function sanitize_bbox( clean, param ) {
 function sanitize_coord( coord, clean, param, latlon_is_required ) {
   var value = parseFloat( param, 10 );
   if ( !isNaN( value ) ) {
-    if( lat_lon_checks[coord].is_invalid( value ) ){
-      throw new Error( 'invalid ' + lat_lon_checks[coord].error_msg );
+    if( coord === 'lat' && check_lat.is_invalid( value ) ){
+      throw new Error( 'invalid ' + check_lat.error_msg );
     }
     clean[coord] = value;
   }
   else if (latlon_is_required) {
-    throw new Error('missing ' + lat_lon_checks[coord].error_msg);
+    throw new Error( util.format( 'missing param \'%s\'', coord ) );
   }
 }
 
@@ -97,18 +97,9 @@ function sanitize_zoom_level( clean, param ) {
   }
 }
 
-var lat_lon_checks = {
-  lat: {
+var check_lat = {
   is_invalid: function is_invalid_lat( lat ){
     return isNaN( lat ) || lat < -90 || lat > 90;
   },
   error_msg: 'param \'lat\': must be >-90 and <90'
-  },
-  lon: {
-    is_invalid: function is_invalid_lon(lon) {
-      return isNaN(lon) || lon < -180 || lon > 180;
-    },
-    error_msg: 'param \'lon\': must be >-180 and <180'
-  }
 };
-