Simplify slider widget drawFace() function.
Use just one loop to draw all minor ticks.
Use a second loop to extend lines for major ticks.
Use totalTicks variable to determine number of ticks to draw.
Handle full signed 16 bit ranges for widgets.
Widgets will now work properly with minimum and maximum values
from −32,768 to 32,767.
Also, place the numeric value field close to sliders
and horizontally centred in gauges.
Merge branch 'slider_ticks'.
Simplified slider widget drawFace() function.