drupal 7.35 .htaccess: Invalid command 'Order', perhaps misspelled or defined by a module not included in the server configuration
The current iteration of the PHP buildpack uses Apache HTTPD 2.4.  The message that you're seeing is caused because you're using configuration that is specific to HTTP 2.2.  

There are two ways to correct this.

1.) Update your configuration to use HTTP 2.4.  Instructions for migrating can be found here.

2.) You can enable the mod_access_compat module for HTTP 2.4.  This will allow you to keep using the older configuration style.  To do this, you should copy this file from the build pack, place it in the root of your project directory under .bp-config/httpd/extra/httpd-modules.conf and uncomment line #27.  Then when you push, the build pack will detect all the enabled module, include mod_access_compat from the configuration file and enable them.

If you have any trouble modifying the build pack configuration, see here for more details.