#33 Building standard windows DLLs

[sskacar]

On \iaxclient\contrib\win\vs2005 solution and projects,
output from Debug_dll and Release_dll configurations build standard windows DLL with the following properties :
- no name mangling
- stdcall calling convention
- msvcrt80.dll independent

After this patch, c/c++ applications using this library as
1. a DLL should define LIBIAXCLIENT_LINK_AS_DLL (as a preprocessor directive.)
2. a static LIB should only rebuild LIB and their applications (BUILDING_DLL directive removed from Debug and Release configurations, hence "#define EXPORT" becomes empty)

Note that listVidCapDevices() referenced in iaxclient.h is an exception at the time. It is not listed in the DEF file anyway.

[sskacar]