Add info about filters being subscriptions (#22)

* Add info about filters being subscriptions

* Fixes broken links

Signed-off-by: Edward Evans <edward.evans@consensys.net>

docs/HowTo/Interact/Filters/Accessing-Logs-Using-JSON-RPC.md

@@ -1,6 +1,8 @@
 # Accessing Logs Using Pantheon API
 
-Access logs using Pantheon API methods:
+Subscribe to events, such as logs, using either [RPC Pub/Sub over WebSockets](../Pantheon-APIs/RPC-PubSub.md) or filters over HTTP.  
+ 
+Access logs by using the following Pantheon API methods:
  
 * [`eth_getFilterChanges`](../../../Reference/Pantheon-API-Methods.md#eth_getfilterchanges)
 * [`eth_getFilterLogs`](../../../Reference/Pantheon-API-Methods.md#eth_getfilterlogs)

docs/HowTo/Interact/Pantheon-APIs/RPC-PubSub.md

@@ -3,10 +3,11 @@ description: Using RPC Pub/Sub with WebSockets
 
 # RPC Pub/Sub over WebSockets
 
-## Introduction 
+## Introduction
 
-Use RPC Pub/Sub over WebSockets to wait for events instead of polling for them. For example, a Dapp can 
-subscribe to logs to be notified when a specific event has occurred.
+Subscribe to events by using either RPC Pub/Sub over WebSockets or [filters over HTTP](../Filters/Accessing-Logs-Using-JSON-RPC.md).
+
+Use RPC Pub/Sub over WebSockets to wait for events instead of polling for them. For example, a Dapp can subscribe to logs to be notified when a specific event has occurred.
 
 Methods specific to RPC Pub/Sub are: