3 lights ( + material and shader injection) implemented and tested on ios, android and rasberrypi

Lot of changes. Please review
So something like this:
from Tangram::render before call to mapTile->draw
```
std::shared_ptr<ShaderProgram> shader = style->getShaderProgram();
for(auto& light : m_scene->getLight() {
    light->setupProgram(*shader);
}
tile->draw(style->getName(), *shader, m_view->getViewProjectionMatrix, m_view->getViewMatrix());
```
and MapTile::draw should look like:

```
void MapTile::draw(const std::string _styleName, ShaderProgram& _shader, const glm::dmat4& _viewProjMatrix, const glm::dmat4& _viewMatrix) { ... }
```