[clang-warning-fix][implicit-null-conversion]
[clang-warning-fix][op-precedence]

Fixes warning from -Wparentheses
[mingw-warning-fix][unknown-pragma]

The #pragma warnings are specific to MSVC; these #pragmas account for roughly half of the produced warnings when compiling with OCE_EXTRA_WARNINGS on MinGW.
[intel-warning-fix][invalid-narrowing-conversion]

Fixes icpc warning about invalid narrowing in initializer lists (struct members are supposed to be Standard_Bytes, i.e. unsigned chars)