template package: generalize the compilation

The package dependencies are now automatically checked during the configure
process using tags into cpp files (Closes #149)
- 'tagdepends' allows to declare package dependencies
- 'tagdynamics' is used to declare a vle dynamic
template: fix  FindGVLE.cmake

GVLE_LIBRARIES was relying on the VLE 1.1 version instead VLE 1.2
template: generalize Find*VLE.cmake files

Find*VLE scripts use now the VLE_ABI_VERSION variable in order to
search VLE libs and includes.