add option to draw value as boxes, not lines (currently only with qwt6 and Byte data)
let the raster provider/interface calculate histogram bin count, and make sure there are no more bins than actual range (max-min) for Int16/32 bands
draw histogram boxes for Int16/Int32 also
add HistogramItem from qwt5 examples for use by histogram widget
implement updateLegend() in HistogramItem
allow to plot histogram as boxes with qwt5, using HistogramItem
change histogram bar outline color from black to lightGray
disable 'Draw as lines' option when raster layer does not contain int bands'
disable raster histogram test until rendering testing is improved (also this test depends on qwt version 5 vs. 6)
add files for raster histogram (Int16 and Float32)
Merge pull request #1213 from etiennesky/histogram_bars

Histogram bars