Add "Developer Communities" To Development Page

* Adds links to the #bitcoin IRC channel, Bitcoin StackExchange, and BitcoinTalk Dev & Tech board to the development page.
    
* Links to that section of the page from the devel docs.

Screenshot:

![2014-10-03-210045_452x338_scrot](https://cloud.githubusercontent.com/assets/61096/4514350/679172ce-4b67-11e4-88f3-aa3d1fd16a34.png)

**BitcoinTalk Quality:** a concern was raised in https://github.com/bitcoin/bitcoin.org/pull/589#discussion_r18311326 about the quality of help on BitcoinTalk. I did a quick, highly-subjective and unscientific survey of the top ten displayed non-stickied posts on the dev & tech board, and the help I saw being provided ranged from adequate to great. Many of the replies I saw came from members of the community whose expertise I trust.

I don't dispute that the forum has trolls and scammers, but I'd recommend it to a friend who needed a place to ask questions.

@saivann If you see anything that can be improved in the translation template stuff (or anything else), please feel free to push directly to the branch.
#bitcoin-dev is for Bitcoin development in general. Contrasted against development that uses Bitcoin (eg, web shopping carts) which seems to have little interest on IRC (channels created for it have died), and contrasted against "would be nice to have in Bitcoin, but we can't right now" which #bitcoin-wizards is for.