add README

Signed-off-by: Petar Koretic <petar.koretic@sartura.hr>
new features

* implement file download
* limit modal popup size so action buttons are always visible
* add minification of css and js files
* pagespeed and yslow optimizations
* remove completion window on outer click
* implement intial save/load functionality - parsing yang files to our
 structure using ladislav's parser and our function for structure
conversion
* add many new statements to yang datastore

Signed-off-by: Petar Koretic <petar.koretic@sartura.hr>