support ctrl-shift-home/end on Windows

fixes issue #2989
Fix a bug where scopes were being duplicated for every single token

This improves scroll performance by generating many fewer span elements
to render lines.
Fix typo in event trigger

destoryed -> destroyed
Update Windows build instructions

Just a few suggested changes to reflect experiences over a few months of building on several Windows machines.
- The Posix tools comment doesn't seem to be applicable (anymore)? 
- Added further instructions when using pre-installed Git.
- Added the frequent issue of first-time build failures (random `node-gyp` errors), which don't reoccur on second try.
- Added a few extra words on opening a new issue, to clarify that appropriate details should be provided, if the issue hasn't been reported before.

Feel free to amend or suggest further changes.
corrected grammar
typo
Merge pull request #3021 from dmnd/patch-1

Fix typo in event trigger
Merge pull request #2994 from jordanbtucker/patch-1

support ctrl-shift-home/end on Windows
Upgrade to apm 0.81
Upgrade to language-yaml@0.12
Export ReactEditorView as EditorView from 'atom' module

Also, remove a few early requires of 'exports/atom.coffee' in the spec
suite that were causing failures.
Base editor dimensions on the wrapper view

The goal is to make the editor behave like a standard block-level
element.

The horizontal behavior is simple: we stretch horizontally to fill our
container.

The vertical behavior is more nuanced. If an explicit height is assigned
on the wrapper view, we honor that height. But if no explicit height is
assigned, the editor stretches vertically so that its contents are
visible.

This prepares us to support mini editors, which need to be 1-line tall
without an explicit height assignment.
Support ReactEditorView construction with params hash
Don't show the gutter when 'mini' is true on React editors
Explicitly assign height of editor-contents when height is auto
Add the 'mini' class to the React wrapper view for mini editors
Don't render invisible characters in React mini editors
Don't set an explicit line height on mini editors

This allows the line height to be styled via CSS. I would actually
like to allow all these properties to be assigned via CSS rather than
explicitly via the settings view, but that can be deferred until the
old editor is removed.
Don't render line decorations on mini editors
Add placeholderText to React editors