Version 1.5.0

Changes since the last release include the following:

• Removal of flush_buffer_when_full option and updates to description of metric_batch_size and metric_buffer_limit to reflect revised behaviour (#74);
• Creation of a new telegraf::output class (#57);
• Fixes for newer puppetlabs-apt module behaviour, updates to buffer limit default to reflect upstream (#63);
• Fixes for tests (#41 and #73).