Some bug fixes

Update grammar from changes in C

Update c

Add CI scripts + linting/formatting grammar.js

feat: rewrite the scanner in C

Revert "add "this" keyword"

This reverts commit 086dd299d4.

Fix AppVeyor CI builds

Update used Windows image and NodeJS version to the latest LTS

Add "this" keyword

breaking change: namespace_definition_name has been renamed to
nested_namespace_specifier and the nesting has been reversed to match
the way normal scope resolution works elsewhere.

identifiers that are part of a namespace_definition are now
namespace_identifier, which matches the identifier node type used in
scope resolution for qualified types.

namespace alias definitions use the new nested_namespace_specifier so
all identifiers are namespace_identifier nodes.

support for top-level "inline" namespace declarations (which are valid
if they are nested in another namespace body).

Fixes #193

Add an action to publish the grammar automatically

breaking changes:
- access_specifier is now a named node in base class clauses
- virtual_function_specifier node has been renamed to virtual

Fixes #184

support attribute in alias declaration