Add support for lib-lib linking in msvc-cpp.

libtool in msvc toolchain can link one static library into another.
So we can pass "staticLibraries" property to "libtool". But we have caveat:
When we compile lib with qt (e.g.), it may shouldn't link its libs. So i suggest create additional option (it shouldn't be so automatic):

property var staticLibrariesLibtool // in windows-msvc.qbs

and then add handling code in "prepare" section.
I've done this , but don't want to attach a patch cause thing it's dirty hack.
Maybe you create some better.