Phase 2: syntax highlighting and colour settings page

- JaiSyntaxHighlighter maps every one of the lexer's token types; asserted over
  the whole corpus (105 distinct token types seen, all mapped)
- JaiHighlightingLexer refines IDENT into built-in types and loop variables for
  colouring only, so the parser never sees them as reserved
- colour settings page with a demo file that is itself asserted to lex cleanly

src/main/resources/META-INF/plugin.xml

@@ -20,6 +20,12 @@
             fieldName="INSTANCE"
             language="Jai"
             extensions="jai"/>
+
+        <colorSettingsPage implementation="dev.hgh.jai.highlighting.JaiColorSettingsPage"/>
+
+        <lang.syntaxHighlighterFactory
+            language="Jai"
+            implementationClass="dev.hgh.jai.highlighting.JaiSyntaxHighlighterFactory"/>
     </extensions>
 
 </idea-plugin>