Doc and readme tweaks.

doc-src/features/forwardproxy.html

@@ -0,0 +1,16 @@
+
+In this mode, mitmproxy accepts proxy requests and unconditionally forwards all
+requests to a specified upstream server. This is in contrast to <a
+href="@!urlTo("reverseproxy.html")!@">reverse proxy mode</a>, in which
+mitmproxy forwards ordinary HTTP requests to an upstream server.
+
+<table class="table">
+    <tbody>
+        <tr>
+            <th width="20%">command-line</th> <td>-F http[s]://hostname[:port]</td>
+        </tr>
+        <tr>
+            <th>mitmproxy shortcut</th> <td><b>F</b></td>
+        </tr>
+    </tbody>
+</table>

doc-src/features/index.py

@@ -4,6 +4,7 @@ pages = [
     Page("anticache.html", "Anticache"),
     Page("clientreplay.html", "Client-side replay"),
     Page("filters.html", "Filter expressions"),
+    Page("forwardproxy.html", "Forward proxy mode"),
     Page("setheaders.html", "Set Headers"),
     Page("serverreplay.html", "Server-side replay"),
     Page("sticky.html", "Sticky cookies and auth"),

doc-src/features/reverseproxy.html

@@ -1,9 +1,11 @@
 
-In reverse proxy mode, mitmproxy acts as a standard HTTP server and forwards
-all requests to the specified upstream server. Note that the displayed URL for
-flows in this mode will use the value of the __Host__ header field from the
-request, not the reverse proxy server.
+In reverse proxy mode, mitmproxy accepts standard HTTP requests and forwards
+them to the specified upstream server. This is in contrast to <a
+href="@!urlTo("forwardproxy.html")!@">forward proxy mode</a>, in which
+mitmproxy forwards HTTP proxy requests to an upstream server.
 
+Note that the displayed URL for flows in this mode will use the value of the
+__Host__ header field from the request, not the reverse proxy server. 
 
 <table class="table">
     <tbody>