Changes to teapot-client between r2 and r3

''Simple command-line based interface to [Teapot]''

"teapot-client" is a command-line interface to [Teapot].  It can be used to list or fetch [Tcl] extensions for a given platform.

Usage:
   1. Listing extensions:
   11. teapot-client list ''operating-system'' ''cpu-arch''
   11. Lists extensions available for the specified operating system to stdout
   2. Fetching extensions:
   22. teapot-client get ''directory'' ''operating-system'' ''cpu-arch'' ''extensions...''
   22. Fetches extensions specified and their dependencies (recursively) into ''directory''`/lib`

Examples:
   1. Fetch "pki::pkcs11" extension and all its dependencies into "`test/lib`": -->     1. Fetch "pki::pkcs11" extension and all its dependencies into "`test/lib`":
$ mkdir test
$ teapot-client get test linux x86 pki::pkcs11
   2. More complex example -->     2. More complex example: see [teapot-starkit2exe-makefile]
[@include teapot-starkit2exe-makefile]

Legend

     Only in r2
     Only in r3
     -->      Modified slightly between r2 and r3