Add external library selection (#194)

* Add sound library

Only injected the sounds.js file

* Add injections for two other scripts

* Add sourceLibraries definition

* Add state definition for playgroundLibrary

And also make sourceLibraries definition more concise

* Add display for library selection

* Format files

* Add actions

* Add saga for selecting library

And fix an action typo

* Fix implicit never[] typing

* Add reducer

* Pass dispatch from container down to ControlBar

And also fix some bugs

* Change playground library value in state

* Add comment

* Format files

* Add graphics and low-level list library

* Update Grading's  handleResetAssessmentWorkspace

This was supposed to use to the same one as Assessment, but was not
updated. It has been upated now, my bad.

* Add chapter and externals update for Assessment

Note that the changes in Grading already reflect this

* Format a file

* Add externals for mockLibrary

* Make createDefaultWorkspace take in context args

This is to allow easier reset of workspaces

* Format & add createDefaultWorkspace documentation

* Update js-slang to 0.1.3

* Change Playground prop name

* Rename ControlBar props

* Rename in reducers/states

* Rename for workspaces reducer

* Rename StateProps result in PlaygroundContainer

* Reorder imports

* Rename folder

Author: remo5000

package.json

@@ -37,7 +37,7 @@
     "draft-js": "^0.10.5",
     "flexboxgrid": "^6.3.1",
     "flexboxgrid-helpers": "^1.1.3",
-    "js-slang": "0.1.1",
+    "js-slang": "0.1.3",
     "lodash": "^4.17.10",
     "lz-string": "^1.4.4",
     "node-sass-chokidar": "^1.3.0",