Text file editing

[kof]

1. allow uploading/creating text files from assets panel
2. click on asset opens text editor instead of canvas
3. extend assets resource with some form of query language or UI to allow selecting not all assets but specific extension, file name, include it's contents or not. Exact capabilities here need to be specified based on use cases we can think of. If asset is JSON type, we should be able to parse it as object.
4. Now user can bind on any bindable field any data from assets