WIP: Capture command usage

I'm curious what general command usage patterns are. I want to experiment with tracking all command usage minus editor and core commands. I plan on tracking them like this:

```coffee
sendEvent('command', 'find-and-replace', 'find-and-replace:toggle', 12)
```

This should give us options for drill down. We can group by package, group by command name, and even see how many times people generally run these commands. 

I ran mine for a couple of hours while working on https://github.com/atom/atom/pull/4061. Here are the results:

```
application:open: 2
autocomplete:toggle: 2
block-travel:move-down: 172
block-travel:move-up: 140
block-travel:select-down: 16
block-travel:select-up: 20
command-palette:toggle: 3
find-and-replace:focus-next: 6
find-and-replace:select-next: 87
find-and-replace:show: 2
fuzzy-finder:toggle-file-finder: 22
key-binding-resolver:toggle: 4
pane:show-next-item: 161
pane:show-previous-item: 166
project-find:show: 4
settings-view:open: 1
snippets:expand: 23
snippets:next-tab-stop: 23
symbols-view:toggle-file-symbols: 1
tree-view:expand-directory: 1
tree-view:move: 1
tree-view:open-selected-entry: 2
tree-view:remove: 1
tree-view:toggle: 12
tree-view:toggle-focus: 1
window:focus-next-pane: 2
window:toggle-dev-tools: 5
```

Too much data? Will it become too chatty?
This is not pretty all around. @nathansobo you have any suggestions on getting all the commands from the keyboard and command-palette?