The flag needs to be set for Mac users using clang as well

* Clarifies which system is control over time and camera at what time
* Fixes #1845
* Prevent invalid switching between session recoring and camera path playback
* Some cleanup, mosly of SessionRecording and NavigationHandler. Also, remove ExternInteraction and some other unused/nonexisting functions

Makes the script propagate to all nodes, as well as being recorded during session recording

To avoid potential future problems with scriptscheduler time progressing when simulation time doesn't

Also removed undefined function and do tiny refactor

Note: The dot selector matches all characters. Oops

 - Remove the asset_helper file and call the onInitialize and onDeinitialize functions directly
 - Small compile fix on Windows
 - Removes the need for the registerIdentifierWithMeta function by automatically doing that for all asset.export statements
 - Allow the passing of either identifiers (as before) or entire tables to the removeSceneGraphNode, removeScreenSpaceRenderable, deleteLayer, removeAction, and export methods. In that case, the Identifier key from the table is extracted and used instead

* changes to asset/loader/meta to support adding nodes created at runtime

* update assets meta.

* update tle helper and gui to work with changes

* fixes #1840

* group titan trail and atmosphere with globe

* license for magnetosphere
Co-authored-by: ElonOlsson <olssonelon@gmail.com>

Add more informative error when a layer fails specification;  Add error message when trying to unzip a file that does not exist

Feature/sgct json

* Add some missing renderables
* Tiny refactor of documentation identifiers and log category keys

For consistency. This has bothered me for quite a while

Don't think it should be a breaking change, as the keys in any potential assets are obtained from the codegen/documentation parameters

And make property title formatting more consistent

closes #1822 

Feature/tileproviders