Move everything to javascript dir. Add jspgf API, test files for both Node and web.

src/runtime/javascript/test-node.js

@@ -0,0 +1,33 @@
+const Module = require('./.libs/pgf.js');
+const JSPGF = require('./jspgf.js')(Module);
+const fs = require('fs');
+const path = require('path');
+
+Module.onRuntimeInitialized = () => {
+
+    // Read PGF path from args
+    if (process.argv.length > 2) {
+        const pgfPathHost = process.argv[2];
+
+        // Copy file into filesystem
+        const pgfPathFS = '/tmp/' + path.basename(pgfPathHost);
+        const rawPgf = fs.readFileSync(pgfPathHost);
+        Module.FS.writeFile(pgfPathFS, rawPgf);
+
+        // Read PGF
+        const pgf = JSPGF.readPGF(pgfPathFS);
+
+        // Print its name
+        console.log(JSPGF.abstractName(pgf));
+    }
+
+    // Parse expression
+    const expr = JSPGF.readExpr("Pred (Another (x f))");
+
+    // Show it
+    console.log(JSPGF.showExpr(expr));
+
+    // Print its arity
+    console.log('arity', JSPGF.arity(expr));
+}
+