Uncaught TypeError: Cannot read property 'includeInto' of undefined

[Enter steps to reproduce:]

1. ...
2. ...

**Atom**: 1.28.0 x64
**Electron**: 2.0.3
**OS**: Microsoft Windows 10 Pro
**Thrown From**: [tablr](https://github.com/abe33/atom-tablr) package 1.8.3

### Stack Trace

Uncaught TypeError: Cannot read property 'includeInto' of undefined

```
At C:\Users\User\.atom\packages\tablr\lib\mixins\pool.js:65

TypeError: Cannot read property 'includeInto' of undefined
at Function.pool (/packages/tablr/lib/mixins/pool.js:65:11)
at Function.initClass (/packages/tablr/lib/table-element.js:75:10)
at /packages/tablr/lib/table-element.js:2134:31)
at /packages/tablr/lib/table-element.js:2136:3)
at Module.get_Module._compile (~/AppData/Local/atom/app-1.28.0/resources/app/src/native-compile-cache.js:106:36)
at Object.value [as .js] (~/AppData/Local/atom/app-1.28.0/resources/app/src/compile-cache.js:240:29)
at Module.load (module.js:561:32)
at tryModuleLoad (module.js:504:12)
at Function.Module._load (module.js:496:3)
at Module.require (/app.asar/static/index.js:47:45)
at require (~/AppData/Local/atom/app-1.28.0/resources/app/src/native-compile-cache.js:66:33)
at Object.tablrViewProvider (/packages/tablr/lib/tablr.js:152:43)
at Object.viewRegistry.addViewProvider.model [as createView] (~/AppData/Local/atom/app-1.28.0/resources/app/src/package.js:538:51)
at ViewRegistry.createView (~/AppData/Local/atom/app-1.28.0/resources/app/src/view-registry.js:154:34)
at ViewRegistry.getView (~/AppData/Local/atom/app-1.28.0/resources/app/src/view-registry.js:127:25)
at HTMLElement.activeItemChanged (/app.asar/src/pane-element.js:138:33)
at Function.module.exports.Emitter.simpleDispatch (~/AppData/Local/atom/app-1.28.0/resources/app/node_modules/event-kit/lib/emitter.js:27:20)
at Emitter.module.exports.Emitter.emit (~/AppData/Local/atom/app-1.28.0/resources/app/node_modules/event-kit/lib/emitter.js:156:34)
at Pane.setActiveItem (~/AppData/Local/atom/app-1.28.0/resources/app/src/pane.js:443:26)
at Pane.activateItem (~/AppData/Local/atom/app-1.28.0/resources/app/src/pane.js:583:18)
at TablrJson.open (/packages/tablr-json/lib/tablr-json.js:83:10)
at HTMLElement.tablrJsonOpen (/packages/tablr-json/lib/tablr-json.js:17:37)
at CommandRegistry.handleCommandEvent (~/AppData/Local/atom/app-1.28.0/resources/app/src/command-registry.js:384:49)
at CommandRegistry.dispatch (~/AppData/Local/atom/app-1.28.0/resources/app/src/command-registry.js:273:23)
at AtomEnvironment.dispatchApplicationMenuCommand (~/AppData/Local/atom/app-1.28.0/resources/app/src/atom-environment.js:1347:25)
at EventEmitter.outerCallback (~/AppData/Local/atom/app-1.28.0/resources/app/src/application-delegate.js:339:53)
at emitThree (events.js:136:13)
at EventEmitter.emit (events.js:217:7)
```

### Commands

```
-2:33.3.0 core:select-all (input.hidden-input)
-2:32.5.0 core:paste (input.hidden-input)
-2:30.3.0 core:save (input.hidden-input)
-1:56.5.0 core:confirm (input.hidden-input)
-0:20.9.0 tablr-json:open (input.hidden-input)
```

### Non-Core Packages

```
atom-json-editor 0.4.1
atom-wrap-in-tag 0.6.0
auto-update-plus 0.5.8
browse 1.10.8
build 0.70.0
busy-signal 1.4.3
color-picker 2.3.0
ctrl-dir-scroll 0.2.5
find-and-replace-with-prev 0.210.0
intentions 1.1.5
linter 2.2.0
linter-json-lint 0.1.3
linter-ui-default 1.7.1
minimap 4.29.8
multi-cursor 2.1.5
satisfy-dependencies 0.4.2
scroll-searcher 5.2.0
set-syntax 0.4.0
split-diff 1.5.2
sublime 0.5.0
sublime-block-comment 0.5.1
Sublime-Style-Column-Selection 1.7.4
sublime-word-navigation 0.2.0
sublimify 0.10.0
tablr 1.8.3
tablr-json 0.1.0
tag 0.5.0
text-manipulation 0.6.0
```