TODO: 17.12 keep running, read instructions from pipe/socket

And delete trailing whitespace
And rename section 17 to "command line tool" from "client"

Closes #702

docs/TODO

@@ -112,7 +112,7 @@
  16.1 Other authentication mechanisms
  16.2 Add QOP support to GSSAPI authentication
 
- 17. Client
+ 17. Command line tool
  17.1 sync
  17.2 glob posts
  17.3 prevent file overwriting
@@ -124,6 +124,7 @@
  17.9 Choose the name of file in braces for complex URLs
  17.10 improve how curl works in a windows console window
  17.11 -w output to stderr
+ 17.12 keep running, read instructions from pipe/socket
 
  18. Build
  18.1 roffit
@@ -658,7 +659,7 @@ that doesn't exist on the server, just like --ftp-create-dirs.
  with integrity protection) and auth-conf (Authentication with integrity and
  privacy protection).
 
-17. Client
+17. Command line tool
 
 17.1 sync
 
@@ -746,6 +747,13 @@ that doesn't exist on the server, just like --ftp-create-dirs.
  instead. Proposed name: --write-stderr. See
  https://github.com/curl/curl/issues/613
 
+17.12 keep running, read instructions from pipe/socket
+
+ Provide an option that makes curl not exit after the last URL (or even work
+ without a given URL), and then make it read instructions passed on a pipe or
+ over a socket to make further instructions so that a second subsequent curl
+ invoke can talk to the still running instance and ask for transfers to get
+ done, and thus maintain its connection pool, DNS cache and more.
 
 18. Build