Provide a from target id when sharing blocks to another target so that variable conflicts can be resolved.

* Export initial states for each reducer
* combine all gui reducers (excludes scratchPaint and intl)
* combine all initial states to create default guiState for preloading in www
* expect all of the gui state to be accessible at `state.scratchGui`

Update calls to addSprite2 to use new API for adding sprites. Cleanup sprite3 representation for uploading a new sprite from an image.

to target pane, which already has all the needed props.

Fixes https://github.com/LLK/scratch-gui/issues/1064

Alphabetize all the things

Also, delete `static-blocks.xml` which shouldn't have been added in the
first place.

Remove target pane button and actions

Add back putting the sound library in the ui