doc: update readme

_dist/README.txt

@@ -1,20 +1,52 @@
-A file and image uploading host.
+A file / image / paste upload server with a focus on embedding.
 
 Written in Go
 
+You can use contented as a standalone upload server, or you can use the SDK to embed its upload widget into another website.
+
 =FEATURES=
 
-- Drag and drop upload of multiple files
+- Drag and drop uploader, or fallback classic uploader
-- Fallback classic uploader for other browsers
+- Multiple files upload
+- Pastebin upload
+- SDK-oriented design for embedding
 - Mobile friendly interface
-- Preserves upload metadata
+- Preserves uploaded filename and content-type metadata
+- Hash verification (SHA512/256)
+- Options to limit the upload filesize and the upload bandwidth
+
+=USAGE (SERVER)=
+
+`Usage of contented:
+  -data string
+        Directory for stored content (default "")
+  -db string
+        Path for metadata database (default "contented.db")
+  -listen string
+         (default "127.0.0.1:80")
+  -max int
+        Maximum size of uploaded files in MiB (set zero for unlimited) (default 8)
+  -speed int
+        Maximum upload speed in bytes/sec (set zero for unlimited)
+  -title string
+        Title used in web interface (default "contented")
+`
+
+=USAGE (EMBEDDING FOR WEB)=
+
+Your webpage should load the SDK from the contented server, then call the `contented.init` function to display the upload widget over the top of an existing DOM element.
+
+The SDK will run your callback, passing it the file IDs of any uploaded items.
+
+The SDK depends on jQuery.
+
+`
+<script type="text/javascript" src="SERVER_ADDR/sdk.js"></script>
+contented.init("#target", function(/* String[] */ items) {});
+`
 
 =TODO=
 
-- Upload should redirect to a landing page
-- Sample code to integrate with external systems (webui / ...)
-- Switch to SDK-oriented design
-- Pastebin service
 - View upload history / view all uploads
 - Encrypted at rest (anti- provider snooping)
 - Shorter URLs