installTestModules should override previous bindings in the same scope

[dlemures]

If I have a testModule:

testModule {
  bind(A.class).to(B.class)
}

And a real module:

realModule{
  bind(A.class).to(C.class)
}

The testModule binding for A should override the one from realModule if testModule is installed using scope.installTestModules(testModule). The order used to install the modules should not matter.

Right now it does not happen:

scope.installModule(realModule);
scope.installTestModules(testModule); // does not override

[dlemures]

PR merged: #223