All other map bindings are never freed. Setting SFLAG_DYNLOCK if
map_binding != sysmem might only keep a heap memory allocation around
(e.g. after device_reset) that is never used.

We no longer depend on SFLAG_DYNLOCK to create buffers and PIN_SYSMEM
makes sure the address remains constant.

Also lock/unlock the module only on creation/destruction of the object.

Apparently MSDN made up EmfPlusRecordTypeSetGammaValue, it's not in
the SDK headers or EMF+ spec.