Utility macro for CSS maps

[cigitia]

The sablono.core/html macro internally uses sablono.compiler/compile-map-attr and sablono.util/camel-case-keys to convert ClojureScript maps containing CSS attributes to JavaScript maps usable by React, at compile time.

It would be convenient if a similar sablono.core/css macro or some such were created that did the same conversion at compile time by itself, so that style maps could be conveniently be created in other places, and without having to convert ClojureScript map to JavaScript object at every component render:

(css {:font-family "Comic Sans"})
; would expand to #js {:fontFamily "Comic Sans"} at compile time

[r0man]

@cigitia This should now be possible in master with the attrs macro. #108

[cigitia]

Thanks!