add burn operation to the client, server, and protocol (#2)

* add burn operation to the client, server, and protocol

this provides a method for removing files from the server remotely without needing to restart the server
example use case for this is if your server is publicly accessible but you don't expose SSH publicly and you're transferring data between two cloud servers and don't want the data to be stored on the server any longer than it has to be

* updating documentation

README.md

@@ -63,12 +63,19 @@ set.
 
 ## Running
 
+
+### Server
+
 To run a server, just run:
 
     netgiv --server
 
 `netgiv` will run in the foreground and log accesses to it.
 
+### Client
+
+#### Copy
+
 On any client, run:
 
     $ echo "Hello" | netgiv
@@ -79,6 +86,8 @@ To check for success, try:
 
 You should see "hello" echoed on your terminal.
 
+#### List
+
 To check the list of files on the server:
 
     $ netgiv -l
@@ -89,6 +98,8 @@ To check the list of files on the server:
 
 Note that netgiv tries to identify each file based on file magic heuristics.
 
+#### Paste
+
 If you would like to fetch (paste) a particular file:
 
     netgiv -p 3 > file.mov
@@ -98,6 +109,14 @@ Where '3' comes from the information provided in the `-l` output.
 Note that providing no `-p` option is the same as `-p X` where X is the highest
 numbered upload (most recent).
 
+#### Burn
+
+If you would like to remove/delete (burn) a particular file:
+
+    netgiv -b 3
+
+Where '3' comes from the information provided in the `-l` output.
+
 ### Notes on output
 
 Since netgiv is designed to be used in a pipeline, it does not provide any
@@ -129,8 +148,10 @@ to the client - the server must have a config file with an authtoken specified.
 
 ## Temporary file storage
 
-The `netgiv` server will store files in your normal system temporary dir. They will 
-be deleted when the server shuts down (SIGTERM). These files are *not* encrypted.
+The `netgiv` server will store files in your normal system temporary dir. These files 
+are *not* encrypted. They will be deleted when the server shuts down (SIGTERM). If you
+want or need to remove the files before the server shuts down, you can use the 
+[burn](#burn) flag.
 
 ## Window support