Quick update and minor fixes

marked.js:
* Added/removed newlines in tag outputs
* Removed `lang-` prefix from code language

Demo page:
* Removed external javascript code, now it's included at the end of the demo page (less files in projects root and it wasn't really necessary since the script is short)
* TODO: Code must be escaped before being sent to nerdz preview page

Tests:
* Updated expected output (removed/added newlines where needed and replace all `[cur]` occurrencies with `[i]`)