Adding new modules inside the namespace could be breaking change for existing code base
hence add `using namespace::class` for classes newly added to mbed namespace to maintian
backwards compatibility.
MBED_NO_GLOBAL_USING_DIRECTIVE is added to remove auto-addition of namespace
Macro guard `MBED_NO_GLOBAL_USING_DIRECTIVE` is added around namespace, to avoid
polluting users namespace.
For Windows-formatted SD card, it is not partitioned (no MBR), but its PBR has the
same boot signature (0xaa55) as MBR. We would easily mis-recognize this SD card has valid
partitions if we only check partition type. We add check by only accepting 0x00 (inactive)
/0x80 (active) for valid partition status.
deepikabhavnani
Martin Kojtal
ccli8
Juho Eskeli
Yossi Levy