adjusted content of input fields on invalid price
adjusted display of min- and std-price on zero-values
adjusted display of old- / new-price comparison on invalid data
fixed display bug for striped amazon table
added infinity processing to trend profit column
temporary deactivated sorting by pricechange values due to necessary refactoring
made two columns sortable
made Trend column sortable
made trend profit column sortable
improved infinity ordering by newQuantity
refactored Trend sorting to not pay the penalty of computing values probably not needed
externalized sort sanitizing functionality to not obfuse the code
made Marge and Quantities sortable
made ChangePrice and ChangePriceBrutto sortable again
made TargetMarge sortable again
Merge branch 'feature/AddAdvancedSortingCapability' into develop