use with_dict instead of accessing keys from dict.keys() (#150)

[tyxieblub]

No description provided.

[jdauphant]

Kudos for the work @tyxieblub !

[jdauphant]

@flatrocks take care of this change in your custom templates if you update to v2.7:

it may pose a problem for people with custom templates using these variables as they cannot access them with nginx_sites[item].var anymore and should now use item.value.var

[flatrocks]

@jdauphant Thanks for the heads-up!
Urgent for me to get busy on that pull request for adding because also the readme Example 9 (custom templates) is incorrect, too!

[jdauphant]

@flatrocks Oh, thanks, I just fixed the readme.

[flatrocks]

My apologies @jdauphant for not getting to this sooner. I just posted pull request #155 to provide testing for custom templates, and further updated README to match the test.