Nightly test: Update ABCL to 1.5.0
maxima.bat/xmaxima.bat: Use "/" as a path separator.
Crosscompiling: Update Imagemagick + SBCL
Removed obsolete line from maxima.bat.in
Website: Updated reference manual to version 5.40.0
Website: Update manual (PDF + EPUB) to 5.40.0
Crosscompiling: removed double option BUILD_64BIT line from CMakelists.txt
VTK: add a space after the vtkpython call on Windows.