* Upgrade flow to 0.64
This also enables spread operator on jsx on the flow parser:
```js
<div>{...list}</div>
```
I had no idea it was even a thing.
I had to comment out a flow test that no longer parses, but it's no longer in the flow repo and the comment said that it shouldn't be working anyway so I don't think it's going to be a problem.
* Fix build script
* feat(glimmer): initial HTML/Handlebars/Glimmer support
* feat(glimmer): support un-escaped mustache expressions
* fix(glimmer): add 'as |foo|' syntax
* fix(glimmer): support {{foo bar}} syntax
* feat(glimmer): implement all AST types
* feat(glimmer): implement if/else if/else
* test(glimmer): ignore leading/trailing whitespace from AST_COMPARE
* fix(glimmer): do not use trailing slash for void self-closing elements
* chore(build): disable html tests until we can sort out the glimmer dependency
* feat(html): complete rebase on parse5 addition
* Prettier Support For Glimmer VM/Handlebars
Polished Support for Sub Expressions
Added test cases for glimmer primitives
Added support for concat statements
Attempted to make element nodes work
Attempted block statements
Element Nodes are OK
Added support for block elements that are not else-if related
Added support for Else/If
Cleaning up
Rebase
Switch node 4 syntax
Update build
* Removed dead code/partials
* Added new lines to end of test files.
* Rebase after plugin change
* Added ignores to code coverage
* Fix support for node 4 (#1988)
* Fix website on iOS Safari (#1970)
Formatting change:
* Position JSX whitespace (`{" "}`) at the end of lines (#1964)
Lots of small fixes, mainly for TypeScript.