New serve sh with some help texts

`serve.sh -h` shows the following text
```
serve.sh, TiddlyWiki serve script version 0.0.1

Usage:  serve.sh [edition dir] [username] [password] [host] [port]

Optional parameters

        $1 .. editions directory .. full path or relative to current directory
        $2 .. username for signing edits - can be empty like this:
        $3 .. password - can be empty like this:
        $4 .. IP address or HOST name .. defaults to localhost
        $5 .. PORT .. defaults to 8080

        -v .. Version
        -h .. Help

Example 1 ./serve ./edition/tw5.com-server username
Example 2 ./serve ./edition/tw5.com-server "" "" localhost 9090
.. Example 2 defines: empty username, empty password

```
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There is some room for improvements, because it doesn't work well if the script is used in a VM or docker. 
All parameters should be environment variables. ... but that's a later pull request.