Kazari design improvements

[jdesiloniz]

Fixes: #129, #130

This PR adds code to fix several design issues with the Kazari code decorator. Mainly:

• Implemented the design changes added by @israelperezglez to fix layout and CSS issues.
• Kazari no longer has two themes to choose from. Setting for that option removed, now using single CSS stylesheet.
• Retrieving color schemes from the applied highlight.js theme to match the color of the Kazari button bar as better as possible.
• Also matching background color from highlight.js theme to the CodeMirror modal view.
• Adding an SBT setting to configure the CodeMirror theme.
• Switched default theme to solarized-dark.
• Switched default color highlight in CodeMirror to CLike/Scala for better compatibility.

Could you please review, @juanpedromoreno?? Thanks!!

[juanpedromoreno]

LGTM!