utils: fix error on remote command call

The number of arguments was not checked on the call of a remote command
template: fix missing INCLUDE_DIRS for extensions
devs: fix Dynamics::init() with negative Time

We add a check in the vle::devs::Simulation::init(...) function to
ensure that only positive Time are authorized. (Closes #120)
vle: add CXX and CC flags for Clang

By default, only GNU GCC and G++ have -Wall and -Wextra option. We add
option for Clang too.
devs: improve the positive and negative infinity test

From the C99, POSIX.1, for the isinf() function: "the standards merely
say that the return value is  nonzero if and only if the argument has an
infinite value". So, we update the check to test if isinf() > 0 or
isinf() < 0 insteaf of == 1 or == -1.
utils: remove unused variables
test: hide declaration of get_temporary_path

The get_temporary_path() function only necessary when Boost < 1.45 is
installed (Closes #107).
devs: remove unused variable

The FinishView declares an unused variable m_last. We remove it.
vle: use class instead of struct with Pimpl

For the PIMPL idiom, in header file, we use "class Pimpl" and in the
sources files, we use struct Pimpl. We homogenize declaration.
vpz: fix an error message

When adding a model that already exists into the coupled model,
the error message now gives more detailed information on the concerned
models.
vle : fix compilation options handling

Fix error with unhandled compilation option combination (WITH_GTK=OFF &
WITH_GTKSOURCEVIEW=ON) (closes #124).
vle: update NEWS
vle-1.1.0-beta4
devs: add a runtime access to the simulation results

A runtime access to the results has been provided to the RootCoordinator
class via the outputs function.

Be careful, to avoid memory leak, user need to delete newly allocated
value::Map after the deletion of the RootCoordinator. Ok, it's a bad
design but we need to conserve API.

Example:

int main()
{
    vle::value::Map *result;

    {
        vle::utils::ModuleManager mm;
        vle::devs::RootCoordinator rc(mm);
        ...
        result = rc.outputs();
    }

    delete result; // avoid memory leaks.
}
gvle: add an simulation output log