Undefined indexes at installation time

This pull covers a two cases of undefined indexes during install time.  One is caused by trying to pull data from the fac_Config table before it is created.  The other is due to missing config elements in install.php for Pagesize, temperature and humidity; since they aren't present in the HTML form, they have null values when later processed...

(Ideally, the configuration "presentation" should be shared between install.php and configuration.php so there's only one place to make changes.)