Do not omit the HTML block names

[novoid]

According to https://github.com/novoid/lazyblorg/wiki/Orgmode-Elements#html

   #+NAME: This is the caption 
   #+BEGIN_EXPORT html
   <a href="http://Karl-Voit.at">Link to my webpage</a> 
   #+END_EXPORT

... results in:

   <a href="http://Karl-Voit.at">Link to my webpage</a> 

... without any caption/name.

Implement HTML block captions.

[novoid]

https://github.com/novoid/lazyblorg/blob/master/testdata/end_to_end_test/comparison/2014/01/30/full-syntax-test/index.html demonstrates that the caption is actually working.