Draft: DO NOT MERGE run tests on windows

Beware this has to be rebased, it's just a big messy commit.

And some of the modifications might not be needed to make it work, just leftovers from trial and error.

So this can be separated in several topics:

• The windows declspec(dllimport/export) funny part. It is not done properly, we use a lot of preprocessor variables to set them (_TANGO_LIB, _USRDLL, TANGO_HAS_DLL, LOG4TANGO_HAS_DLL, LOG4TANGO_BUILD_DLL), while 1 should be enough
• There are some cmake issues, to set said variables and some smaller issues.
• Some refactoring helped in fixing some overloading resolution problems.
• And there was some linux specific code.
• I noticed during this work the existence of ranges_const2type and ranges_type2const traits. On the !885 (merged) I introduced tango_type_traits, which does more or less the same, I would like, if this get merged to get rid of one or the other as they do the same (I'll go for keeping tango_type_traits)
• We have to fix the compilation warnings, I'll get started on that.