Correctly fixes issue with Puppeteer hanging (without calling process.exit manually) which exhibited with mocha hanging on travis.

Author: zachleat

cmd.js

@@ -96,7 +96,7 @@ if( argv.version ) {
 			fontface.writeCSSFiles();
 		} catch(e) {
 			console.log("GlyphHangerFontFace Error: ", e);
-			process.exit(1);
+			process.exitCode = 1;
 		}
 
 		try {
@@ -105,17 +105,15 @@ if( argv.version ) {
 			}
 		} catch(e) {
 			console.log("GlyphHangerSubset Error: ", e);
-			process.exit(1);
+			process.exitCode = 1;
 		}
 
 		try {
 			fontface.output();
 		} catch(e) {
 			console.log("GlyphHangerFontFace Error: ", e);
-			process.exit(1);
+			process.exitCode = 1;
 		}
-
-		process.exit();
 	})();
 } else { // not using URLs
 	if( argv.subset ) {

src/GlyphHangerEnvironment.js

@@ -166,11 +166,14 @@ class GlyphHangerEnvironment {
 	}
 
 	get env() {
-		if(this.envStr === "jsdom") {
-			this._env = new JSDOMEnvironment();
-		} else {
-			this._env = new PuppeteerEnvironment();
+		if( !this._env ) {
+			if(this.envStr === "jsdom") {
+				this._env = new JSDOMEnvironment();
+			} else {
+				this._env = new PuppeteerEnvironment();
+			}
 		}
+
 		return this._env;
 	}