* Try to enable all webidls
* Separate out unavailable webidl files by reason.
* Create record of fully tested WebIDL files
* Update notes to reflect new situation with web-idl
* Make a blank ident fail, disable the necessary widls.
It turns out that all the blank idents came from blank enum variants,
which is allowed in webidl apparently.
Not a lot of attention has been paid to dealing with conflicts of symbols
between crates and different `#[wasm_bindgen]` blocks. This commit starts to fix
this issue by unblocking #486 which first ran into this. Currently there's a bug
where if two independent crates bind the same JS API they'll generate the same
symbol which causes conflicts for things like LTO or linking in general.
This commit starts to add a "salt" to all symbols generated by `wasm-bindgen`
(these are all transparent to the user) to ensure that each crate's invocations
are kept apart from one another and using the correct bindings.
This sets the `catch` flag on the emitted AST when an operation/attribute has
the `[Throws]` extended attribute on it.
Additionally, constructors aren't annotated with `[Throws]` but can still throw
exceptions, so we must conservatively assume *every* constructor can throw an
error.
