This removes a race condition between both qwt and qt against math.h on
windows with _USE_MATH_DEFINES set. If math.h comes after qwt or qt
math headers the math defines will be redefined. Really nasty to track
down and ordering problems. So instead I just removed using math
defines on windows and fall back to asin definition of M_PI_2. This
will have some slight perf impact since it calls function instead of
using constant. But I doubt on any of today’s machine it really makes a
difference.

Pulled fixe from latest eigen across. Figured it was safer to patch
than to pull across whole new version of eigen.

This reverts commit fcfb392e.

Start move to single column layout for advanced parameters; Fix
crashing bug in PrimaryFlightDisplay when uas is removed and then
re-added; workaround compiler warning in GeneralBlockPanelKernel,

This reverts commit 233a1716.

Without this change, the program can not be built on Linux.