docker: revamp docker set up to allow for an LN test cluster

This commit revamps the existing docker configuration to allow for
developer’s to easily bring up/down a Lightning Network testbed
environment.

Configuration related bugs within the prior swarm set up have been
fixed. The launched lnd nodes are now able to properly communicate with
the primary btcd node over RPC. The auto-generated RPC script has been
scrapped in favor of hard-coding a developer-only set of RPC
credentials. With this change, it’s now possible to add/remove
additional lnd nodes in order to test more complex scenarios.

Additionally, the containers now build off of the latest Go version
(1.7).

docker/docker-compose.yml

@@ -1,20 +1,27 @@
 version: '2'
 services:
     btcd:
-        container_name: btcd
-        build: btcd/
-        ports:
-            # TODO(roasbeef): switch to testnet after fixing peer discovery.
-            - "28901:28901"
+        environment:
+            - RPCUSER=devuser
+            - RPCPASS=devpass
+        build: 
+            context: btcd/
+        expose:
+            - "18336"
         volumes:
-            - shared-volume:/data
+            - shared-volume:/rpc
     lnd:
-        container_name: lnd
-        build: lnd/
-        ports:
-            - "10009:10009"
+        environment:
+            - RPCUSER=devuser
+            - RPCPASS=devpass
+        build: 
+            context: ../
+            dockerfile: docker/lnd/Dockerfile
+        expose:
+            - "10009"
+            - "10011"
         volumes:
-            - shared-volume:/data
+            - shared-volume:/rpc
         links:
             - btcd
 volumes: