update modificateDate index at load time
move background indexes when finalizing

Move background indexes instead of copying them on the filesystem when
finalizing.
tidy up background index comments and help
add ability to test indexes built in live mode
correctly handle Record metadata accumulation

Clear database metadata when clearing indexes. Accumulate Record
metadata when indexing.
do not store record with empty identifiers
remove excess debug messages when loading
remove unnecessary Index selector config
streamline component indexing

Do not descend into sub-components when indexing components for description
and anywhere indexes.