Misc minor edits.

Added reference to RWD.
Fixed some links.
Formatting, some grammar.

Signed-off-by: Jonas Bonér <jonas@jonasboner.com>
Changed definition of 'non-blocking'
Removed reference to 'Smart Batching'
Merge pull request #4 from reactivemanifesto/wip-misc-improvements-to-responsive-section-jboner

Misc improvements to Responsive section.
Added reference to RWD.
Fixed some links.
Formatting, some grammar.
Changed definition of non-blocking. 
Removed reference to Smart Batching.