Commenting and housekeeping

A mismatch between the desired name of the plugin and the actual js file
name has been corrected. Also commenting for the whole plugin improved/
added. Slight changes to the layout and code just to streamline it a bit
.
Wrong file linking in demo html file

After changing the plugin name to the correct one I forgot to change the
file linking to reflect it.

changed index.html script src gridSlide.js instead of gridJs.js
Merge Dev into Master

Merging dev branch into master. Code layout improved and commenting also
 improved.