Reverts commit 10481f2f7e partially.
Changes made to ExhaustibleBlockDevice hides simulated flash degradation
which is the assumed behavior. Converted back to original behavior.
Incorrect addresses only cause error return values instead of assertion.
ExhaustibleBlockDevice has working get/set_erase_cycle functions and an
array preventing programming without erase.
Fixed MBRBlockDevice partitioning function.
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.