Various fine tuning fixes.

The nav bar when the window is scrolled decrease size.
Some corrections to the demo section buttons.
Change the style of the demo section to make it always visible.
Implement a carousel for the "itWork" section.
Implement post-image loading for "demo" section and "itWork" section.
Change tablet trigger from 791px to 990px.
Insert the "login" and the translate button in the scroll down mobile header.
Some corrections to the carousel and the nav menu.

Correction in the Gruntfile.js.

Correct the installation process for Windows in install.sh.
Merge pull request #8 from uCtrl/landingPageFinalisation

Landing page finalisation