Make Gunicorn respect config.json settings

- Updated gunicorn.conf.py to read host/port from config.json
- Added gunicorn section to config.json for server settings
- Created start_gunicorn.py as alternative launcher
- Updated config.json with server settings (127.0.0.1:6969)
- Updated documentation with new startup options

config.json

@@ -1,10 +1,17 @@
 {
   "app": {
     "name": "ircquotes",
-    "host": "0.0.0.0",
-    "port": 5050,
+    "host": "127.0.0.1",
+    "port": 6969,
     "debug": false
   },
+  "gunicorn": {
+    "workers": 4,
+    "timeout": 30,
+    "keepalive": 5,
+    "max_requests": 1000,
+    "preload": true
+  },
   "database": {
     "uri": "sqlite:///quotes.db?timeout=20",
     "pool_timeout": 20,