introduces new image being displayed, when no articel is selected
changes button layout for future changes
changes image_preview to have more information
centers preview box vertically
added new default article preview image
modified install script accordingly
added overview over last 3 prices, where available
colorizes the current price in the preview box
makes max title length in the preview box slightly larger
fixes duplicate articles being written to the data file
dirty fixes gui problem after deleting article
now dynamically resizes the preview picture, so the longer side becomes 100px long
Merge branch 'new-layout' into development