Add second part of the debugging guide
:checkered_flag: Use ctrl-alt-shift-p for logging

Previously this was bound to both log cursor specs and run package
specs and run package specs seemed to be a more valuable and commonly
run command.
Use process.exit
:penguin: Use ctrl-alt-shift-p for logging cursor scopes
Reorder if/else check
:checkered_flag: Don't crash when closing spec window

Focusing the window during the blur event that fires when the
window is closed currently crashes the app on Windows.

Closes #2485
Merge pull request #2457 from atom/cj-add-python-check

Create requirement verifier for script/bootstrap
Upgrade to language-python@0.18
Upgrade to settings-view@0.119
Add concrete install instructions for Fedora Linux
Add underlayer an overlayer classes to the correct elements
Add getFirstVisibleScreenRow and getFirstVisibleScreenRow
Add active property
Use Editor::getVisibleRowRange instead of the rendered row range

The rendered row range is larger than the visible row range to force the
DOM to break up repaints. This is a more accurate method to us.
Add ReactEditorView::getFontSize
Add ReactEditorView::setWidthInChars shim
Add the ReactEditorView::updateDisplay shim
Add ReactEditorView::setText
Add ReactEditorView::isFocused shim
Upgrade to language-sass@0.12