Improve setup documentation for Twitter module

Notes taken just now while testing a couple of unrelated issues.

Posting to Twitter.

1. Download Twitter and dependent modules.

Dependencies: 
 - for 7.x, Twitter Post and Twitter Signin depend on OAuth
 - for 6.x, Twitter Post and Twitter Signin depend on OAuth (and OAuth depends on Autoload).

2. Enable the relevant modules.

3. Configure your Twitter application.

 - Visit the Twitter module configuration screen.
   - admin/config/services/twitter for D7
   - admin/settings/twitter for D6
 - Copy the Callback URL on the module configuration screen.
 - Visit https://dev.twitter.com/apps and create an application for your website.
   - Name, Description and Website are yours to choose.
   - Callback URL should be the value suggested on the module configuration screen.
 - Complete the Twitter Application configuration.
 - On the module configuration screen, update the OAuth Consumer Key and OAuth Consumer Secret with values provided by the Twitter application page.

4. If posting to Twitter, configure the content types to enable posting for.

 - Visit the Post configuration screen.
   - admin/config/services/twitter/post for D7
   - admin/settings/twitter/post for D6
 - Enable to content types you wish posted to Twitter.

5. If posting to Twitter, configure your account to post as.

 - Edit your user and then select the Twitter Accounts page.
   - user/%uid/edit/twitter for D6 and D7
 - Click 'Add Account' to authorise your Twitter app for your account.
 - Optionally, use 'Make global' to permit all users to post using this account.

6. Twitter Sign-in

to be continued ...

Also, http://drupal.org/node/1361938#comment-5411616

After carefully following all advice I have managed to get this working. It appears the order in which you install/authorise/activate things is very important. For the sake of helping others, here are the necessary steps I took to achieve auto posting to Twitter:

On Drupal 7.9

1) Download and install Twitter module (activating only main module, not sub modules)
2) Create Twitter App
3) Change App permissions to Read & Write
4) Reset Application keys to obtain new consumer key & secret
5) Add Twitter account in Drupal User admin (/user/[user_number]/edit/twitter)
6) Run cron and check that twitter statuses are shown in user area (/user/[user_number]/tweets)
7) Download and install OAuth module
8) Add Twitter App Consumer key & secret to Drupal > Configuration > Web Services > Twitter
9) Activate Signin with Twitter submodule
10) Log out of Drupal and Sign back in using Twitter account (it works)
11) Activate Twitter Post & Twitter Actions sub modules
12) Choose content types to automatically post in Drupal > Configuration > Twitter > Post
13) Add new content
14) Check twitter - it works!!

NB: It is not necessary to sign in to the Drupal admin with your Twitter account to have posts automatically post to Twitter.

In my experience (as per first comment), some of the above is not necessary - you can enable all modules at once, for example.

notes while testing #1361938: Not posting to Twitter

Yes, I've seen that page. This issue really about the fact that we have lots of support requests for configuration, and that there are multiple documented approaches to config, some involving steps that are really just voodoo.

Ideally I'd like us to have an INSTALL.txt which matches the contents of the docs page on d.o.