GUI: Added ESLint to gulp tasks
GUI: Linted files
Fixed an error in the build script

JIRA-TASKS: ONOS-6522, ONOS-6521

Change-Id: Ie72abfe6cbe21c8946f219be6193344b67ec6dd1
diff --git a/tools/gui/gulp-tasks/index.js b/tools/gui/gulp-tasks/index.js
index 3bef084..2f2019b 100644
--- a/tools/gui/gulp-tasks/index.js
+++ b/tools/gui/gulp-tasks/index.js
@@ -1,2 +1,5 @@
 export { default as BundleJS } from './bundles/bundle-js';
-export { default as BundleCSS } from './bundles/bundle-css';
\ No newline at end of file
+export { default as BundleCSS } from './bundles/bundle-css';
+export { default as Lint } from './lint';
+export { default as DevServer } from './dev-server';
+// export { default as Tests } from './unit-tests';
\ No newline at end of file