Add Token module support (provide tokens)

Link module

As adding code in the main module file and/or keeping it lean and tidy is desirable for you, I can reroll the patch but placing the token functionality in a sepatare contactinfo.token.inc file to take advantage of token module implementing hook_hook_info:
https://api.drupal.org/api/drupal/modules!system!system.module/function/...
This way you'll keep the token functionality out of sight. Also, it will be loaded only when needed, good for performance.

The proposed functionality would just enhance the module without any end-user noticing, but would allow more site devs to do fancy things with it (multisites and distributions come to mind).

I agree on the need to provide the remaing contact fields, too. But creating a new module just for this simple functionality looks overkill to me. Just adding now and placing a "initial token support" banner linking here in the module page would make the module sexier to site devs ;)

Just two small changes:
* As per UI guidelines, using ' instead of ’ for "site's".
* Changed printing-style double quotes (“Personal”) to regular, since in my non-English browser, they displayed weird chars. Also, as per UI guidelines, regular double quotes are used everywhere.

Here are the patch interdiffs:

18c29
< +    'description' => t('Tokens for this site’s contact information.'),
---
> +    'description' => t('Tokens for this site\'s contact information.'),
23c34
< +    'description' => t('Either “Personal” or “Organization/Business”.'),
---
> +    'description' => t('Either "Personal" or "Organization/Business".'),
27c38
< +    'description' => t('Site contact person’s first name.'),
---
> +    'description' => t('Site contact person\'s first name.'),
31c42
< +    'description' => t('Site contact person’s last name.'),
---
> +    'description' => t('Site contact person\'s last name.'),
83c94
< +    'description' => t('This site’s contact email address.'),
---
> +    'description' => t('This site\'s contact email address.'),

Other than those two, the attached patch is the same which works great in my tests. Thank you very much.

Ops. I was basing #2 in an assumption based on my above referenced and linked page alone. I recall seeing there to use " quotes somewhere. Checked your provided references and put back smart quotes, but using HTML entities this time. They display OK in my browser, now.

Also, bookmarked the nice http://smartquotesforsmartpeople.com/ . Thanks for the link. Since I'm under Ubuntu, here's how to pull smart quotes on Ubuntu, for completeness.

Patches interdiff:

18c29
< +    'description' => t('Tokens for this site’s contact information.'),
---
> +    'description' => t('Tokens for this site\'s contact information.'),
23c34
< +    'description' => t('Either “Personal” or “Organization/Business”.'),
---
> +    'description' => t('Either &ldquo;Personal&rdquo; or &ldquo;Organization/Business&rdquo;.'),
27c38
< +    'description' => t('Site contact person’s first name.'),
---
> +    'description' => t('Site contact person\'s first name.'),
31c42
< +    'description' => t('Site contact person’s last name.'),
---
> +    'description' => t('Site contact person\'s last name.'),
83c94
< +    'description' => t('This site’s contact email address.'),
---
> +    'description' => t('This site\'s contact email address.'),

Great to see it added to the module, thanks.
Too bad about the quote issue, now that I was already sold on it.
Minor issue: add this to the project description feature list.