win32: rely on native compilation

- boost dll are used rather than static libs
- static vle libraries are removed
- cpack is modified for native compilation
win32: fix m_prefix path setting

m_prefix was initialized using HKEY_CURRENT_USER even if it is not set
win32: fix requirements for gtk+

gvle.glade required gtk+ version 2.24 whereas win32 binaries of gtkmm
provide gkt+ version 2.22
win32: fix missing VLE_APi export symbol

VLE_API symbol was missing for operator<< in ExternalEventList
gvle: fix missing output directory while running

when running a simulation from gvle, the output directory of the
current package is required
utils: fix test_package

- take into account the separation of binaries and sources
- add the boost/version.hpp include
template pkg : update the cmake files

- update the template package using the new Find_VLE cmake scripts
- compile tests using shared libs of boost
gvle: remove header

The `iostream' header is duplicated in the main file.
utils: improve the Package class

We prefer to use the default constructor and the clear() function
instead of ` = ""'.
package: fix typo

Fix typo in four CMake scripts.