Make images that are not ready yet "position: absolute", so they do not not occupy space in the thumbnails-list.
Otherwise with "thumbnails: lazy" and thumbs loaded at the beginning and the end of the container, the length of the
 "thumbnails"-container will be too short and the last thumbnails get pushed to the next line.
 Experimental "ondemand"-loading of thumbnails.
 The option `thumbnails: 'ondemand'` can be set in order to load thumbnails  when needed:
  * Thumbnails that are in the visible range of the thumbnails-view are loaded
  * Thumbnails, that are adjacent to the visible range (one carousel-width before or after) are loaded.
  * As the carousel moves, more thumbnails are loaded.
Update README
Merge remote-tracking branch 'aino/master'

Conflicts:
	README.rst
on-demand chunk-size is now configurable by option 'onDemandChunkSize' (default 5)
Ensure that the carousel moves at least one picture in the desired direction, even though too few images are displayed.
Updater README.rst: "Ensure that the carousel moves at least one image in the desired direction, even if to few images fit into it."
Better prevention of wrongly computed thumbs-container-width with lazy thumbnails
This is a fix for commit "5ed3ca89748aa6302cd294f207696e2abb521266".
This commit made sure that lazy loaded images are displayed "position:absolute" until they are loaded, in order to make sure they do not occupy space in the thumbscontainer. The side-effect  was (in IE 10) that images where displayed for a short time in the left corner of the container after loading, until the position was set to "relative" in "_carousel.update()".
This commit also uses the width of not-yet-loaded image containers for computing the total with of the thumbs-container and makes sure that these images get maximal height so that following images really have the expected position.
The first image was not displayed in some setups, when "load=ondemand" was configured.
Bugfix: In some rare cases, updateCarousel() is called before any thumbs are loaded.
In such a case, the load method lwas loading the previous images and images ahead, but the the current (i.e. the first) image.
Merge remote-tracking branch 'origin/pr/311'