Please help me in solving these warnings, in order to submit the theme for submission. Thanks in Advance.

I have found many warnings and have solved many of them thanks to wordpress.stackexchange.com but still unable to solve the below arors, please help me.

WARNING: Found base64_encode in the file twitteroauth.php. base64_encode() is not allowed.
Line 123: return base64_encode(hash_hmac('sha1', $base_string, $key, true));
Line 203: return base64_encode($signature);

WARNING: Found base64_decode in the file twitteroauth.php. base64_decode() is not allowed.
Line 207: $decoded_sig = base64_decode($signature);

WARNING: file_get_contents was found in the file twitteroauth.php File operations should use the WP_Filesystem methods instead of direct PHP filesystem calls.
Line 277: file_get_contents(self::$POST_INPUT)

WARNING: curl_init was found in the file twitteroauth.php File operations should use the WP_Filesystem methods instead of direct PHP filesystem calls.
Line 1084: $ci = curl_init();

WARNING: curl_exec was found in the file twitteroauth.php File operations should use the WP_Filesystem methods instead of direct PHP filesystem calls.
Line 1110: $response = curl_exec($ci);

REQUIRED: plugin-activation.php. Themes should use add_theme_page() for adding admin pages.
Line 335: add_submenu_page(

REQUIRED: innovative_panel_functions.php. Themes should use add_theme_page() for adding admin pages.
Line 143: add_menu_page(theme_name.' Settings', theme_name ,'install_themes', 'panel'

RECOMMENDED: Possible variable $instance found in translation function in plugin-activation.php. Translation function calls must NOT contain PHP variables.
Line 2043: echo '<p><a href='' . add_query_arg( 'page', TGM_Plugin_Activation::$instance->menu, admin_url( TGM_Plugin_Activation::$instance->parent_url_slug ) ) . '' title='' . esc_attr( TGM_Plugin_Activation::$instance->strings['return'] ) . '' target='_parent'>' . __( TGM_Plugin_Activation::$instance->strings['return'], 'tgmpa' ) . '</a><