win32: fix m_prefix path setting

m_prefix was initialized using HKEY_CURRENT_USER even if it is not set
win32: remove temporarly test_package

test_package (in utils) is temporarly removed,
it requires specific win32 api fixes.
win32: fix requirements for gtk+

gvle.glade required gtk+ version 2.24 whereas win32 binaries of gtkmm
provide gkt+ version 2.22
cli: fix the wrong copy of template pkg

The template package was created even if the directory was present into the
current directory (Closes #70)
win32: fix missing VLE_APi export symbol

VLE_API symbol was missing for operator<< in ExternalEventList