Ability to choose which Layers to compile

[mueschm]

Add two pre-processor flags for each layer that allow you to control how they will be compiled into your application. By default all layers are added and there is no change to how the SDK is currently compiled in master. This will give people who use compile the SDK by source to choose which layers they want in their build process without the need for maintaining any additional code.

LAYER_{LAYER_NAME}_DISABLE_ALL

Removes the layer completely from your application

LAYER_{LAYER_NAME}_DISABLE_RUNTIME

Adds the layer but only to the core. The goal with calling this flag RUNTIME was to allow it to both be used by Andriod and iOS so the flags would match.

[pozdnyakov]

Thanks for your patch! Few comments:

1. We should also set annotationsEnabled to false if any of line, fill or symbol layers is disabled.
2. Could you also update https://github.com/mapbox/mapbox-gl-native/blob/master/platform/darwin/src/MGLStyleLayerManager.mm and https://github.com/mapbox/mapbox-gl-native/blob/master/platform/default/src/mbgl/layermanager/layer_manager.cpp accordingly?

[mueschm]

@pozdnyakov I have made the suggested changes. Though was not fully clear on the parameters necessary to disable annotations, so I did this. Basically if any of the line, layer or fill layers are completely disabled then annotations is set to false. However if they are all set to core then the annotations are still enabled.

#if defined(MBGL_LAYER_LINE_DISABLE_ALL) || defined(MBGL_LAYER_SYMBOL_DISABLE_ALL) || defined(MBGL_LAYER_FILL_DISABLE_ALL)
const bool LayerManager::annotationsEnabled = false;
#else
const bool LayerManager::annotationsEnabled = true;
#endif

If that is not correct let me know and I will up date it

[mueschm]

So there seems to be a test failing for node. However I cannot reproduce this locally at all. Any possible way to get some more insight on this?

[pozdnyakov]

May I ask you to squash commits before merge?

[pozdnyakov]

May I ask you to squash commits before merge?

To be clear, could you make a single commit out of the present 6 ones with a common description of the change (not just the commit messages of all the squashed commits)?