Clean up util namespace, remove unused functions
Remove superfluous stylesheet namespaces

This removes the garden.stylesheet.{functions,pseudo-classes,selectors}
namespaces. These namespaces, while convenient, should not be included
with this library as they add extra code which would be better suited
elsewhere (like in another library).
Remove font-family function

See previous commit for why.
Rename indent-location to indent-location-re
Ignore more Emacs nonsense
Fix broken tests
Remove accidentally added file
Replace CSS{Import,Keyframes,MediaQuery} with CSSAtRule

Since CSS has several at-rules, and it would be nice if Garden could
target all of them, it makes sense to have a single type which
represents them.

The constructor requires an identifier and value. The identifier being
the name of the at-rule and the value being any type (although this is
usually will be a map).

The expansion and rendering process can now simply dispatch on the
CSSAtRule type which in turn uses a multimethod to determine the
correct action.

Perhaps at some point the same sort of refactoring could be applied to
the remaining Garden types (CSSUnit and CSSFunction).
Make vendors function private
Minor reorganization
Add Compilation heading
Minor doc tweak
Add/clean documentation
Add tests for defcssfn and defkeyframes
Move expand-at-rule :default
Update ChangeLog
Remove meta-as-media-query information in README
Merge branch 'master' of https://github.com/noprompt/garden into cljs

Conflicts:
	src/clj/garden/repl.clj
	src/cljx/garden/compiler.cljx
	src/cljx/garden/def.cljx
	src/cljx/garden/stylesheet.cljx
	src/cljx/garden/util.cljx
	test/garden/compiler_test.cljx
	test/garden/def_test.cljx
	test/garden/stylesheet_test.clj