HTML code quality

[vast]

• removed messy conditional comments since we support IE8+ (and it doesn't always require CSS fixes)
• fixed google_analytics_tag in development
• updated jquery version to 1.10.2
• removed empty meta[name=description]
• set initial scale as 1 in viewport meta tag
• fixed url for html5shiv

[timurvafin]

@vast what you think if we will replace current markup with simple bootstrap template?
And isn't it better to include query with rails-assets?

[vast]

@timurvafin, sorry for taking so long to reply.

I'm going to work on JS issues in another PR. Sure, will look for a better jQuery approach.

As for the bootstrap template, I'm not sure that we can choose one proper version at this moment. There is 3.0.3 version which is not so stable (and some people simply switch back to 2.3.2) and good old 2.3.2 which is consistent and well-tested.

I'd suggest using bootstrap after bootstrap 3.1 release.