:lipstick: Deprecate backspaceToBeginningOf{Word,Line}

Rename functions `backspaceToBeginningOfWord` to `deleteToBeginningOfWord` and
`backspaceToBeginningOfLine to `deleteToBeginningOfLine`.
Rename commands `editor:backspace-to-beginning-of-word` to
`delete-to-beginning-of-word` and `editor:backspace-to-beginning-of-line` to
`editor:delete-to-beginning-of-line`.

Fix #1791
:memo: Add more Emoji to the contributing guide

Suggest Emoji for:
 - Fixing something on Mac OS
 - Fixing a bug
 - Burning whitespace
 - Fixing the CI build
 - Adding tests
 - Refactoring
 - Security
Use :apple: for Mac OS specific bugs
Use :fire: emoji for general deleting of code
Remove :recycle: from the emoji in CONTRIBUTING.md
hide the cursor with cursor-hidden class rather than element.style
merge conflict
Fix subscription leak when ~/.atom/styles.less is present running specs
Merge pull request #2213 from dyross/dyr-hide-cursor-nicely

Hide the cursor with cursor-hidden class rather than element.style
Fix failures running config specs locally
Fix another subscription leakage associated with theme manager specs
Upgrade to autocomplete@0.28.0
Upgrade to apm 0.54.0
Upgrade to tree-view@0.93.0
:penguin: Add keybindings for select-to-top/bottom

ctrl-shift-home/end are now mapped

Closes #2251
Upgrade to language-python@0.16.0
Use div for test workspace element
Check if selector matches parents of test element

Previously a menu for a keybinding with a .workspace selector would not
display the shortcut because the selector wasn't matching the test editor
element directly.

Now the parent elements of the test editor are checked as well.

Closes #2089
Bug #1791 Fix typo in example group name and function names.
Check for errors in script/mkdeb

Refs #2129