Fix issue #1706716, PHP warning after D7 cache clear
#1559884: Updating labels for views fields to use field name
fix broken output of tables in test callback.
Feature #1559916, monthly support for periodic method plugin.
document use of db_query_slave.
Merge branch '6.x-1.x' of git.drupal.org:project/sampler into 6.x-1.x
Provide db_query_slave function if it doesn't exist, so the samplers can use it without worrying whether or not it exists.
