Update for win 32

- use static boost libraries for win32
- template: add cmake macro (DeclareVleTest) for test building
- replace SHARED libraries by MODULE for gvle and output plugins
- use FindPackage scripts : FindVLE, FindGVLE, FindVLE_DEPS, FindGVLE_DEPS
- remove DllDefines for extensions (useless for static libraries)
- exs: fix message error for missing difference-equation
- exs: fix missing RandomGenerator constructor implementation
- difference-eq: fix, remove glue directory

(see the corresponding pull request for vle)