Merge commit '3472d77c4af7bce32e7580c2d9ccf3541aec79b9'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'upstream/master'
Correct background region calculation for rotated view in dc-mode
Merge branch 'master' of https://github.com/OpenCPN/OpenCPN
render background chart correctly for raster charts in single chart mode with rotated viewports

this change corrects a7f724b4a62625cbc4cae5b6e254dd6bd2c39e17
I would like to see the coordinates used somehow reworked involving many more changes.
This would simplify the main render code in chcanv.cpp and glChartCanvas.cpp by changing
the calculations for each chart type.

For example, cm93.cpp:5254 really should not be testing for opengl
improve ui for texture cache handling, and support build without opengl
Merge branch 'master' of https://github.com/OpenCPN/OpenCPN
add fallthrough cases for plugin api 1.12
Add improved OpenGL configuration log message.
Merge remote-tracking branch 'upstream/master'
Complete implementation of GL_COMPRESSED_RGB_FXT1_3DFX texture compression cache scheme.
correct Windows build for 3DFX texture compression mode.
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of https://github.com/OpenCPN/OpenCPN
Correct quilt region calculation shortcut, again.
Simplify overzoom blur technique for POT textures.