Add configurable support for angled quotes

The flag `HTML_SMARTYPANTS_ANGLED_QUOTES` was added to Blackfriday on Black Friday. This configures rendering of double quotes as angled left and right quotes (&laquo;
&raquo;).

Typical use cases would be either or, or combined, but never in the same
document. As an example would be a person from Norway; he has a blog in both
English and Norwegian (his native tongue); he would then configure Blackfriday
to use angled quotes for the Norwegian section, but keep them as reqular
double quotes for the English.

This commit adds configuration support for this new flag, configuration that can be set in the site configuration, but overridden in page front matter.

Fixes #605
Added delimit & sort template functions, tests and docs
Added top level .Hugo variable with version, commit and generator information
Added Version, CommitHash and BuildDate to hugolib/hugo.go and used it in build
Removed commitHash and buildDate from commands/version.go and used hugolib vars
Fix hugo version build date format.
Merge pull request #694 from derekperkins/hugo-generator

First pass at adding top level .Hugo variable

* derekperkins/hugo-generator:
  Added top level .Hugo variable with version, commit and generator information Added Version, CommitHash and BuildDate to hugolib/hugo.go and used it in build Removed commitHash and buildDate from commands/version.go and used hugolib vars

Conflicts:
	commands/version.go
Merge pull request #686 from bjornerik/feature/quotes-of-angles

Add configurable support for angled quotes

* bjornerik/feature/quotes-of-angles:
  Add configurable support for angled quotes

Conflicts:
	commands/hugo.go
	hugolib/shortcode.go
Merge pull request #683 from derekperkins/template-functions

Added delimit function, tests and docs

* derekperkins/template-functions:
  Added delimit & sort template functions, tests and docs