When reading offline VSL files (-r ..) make a copy of each matched tags data since the data is volatile.

This is controlled manually by the new 'log.data.copy = true|false' config property
which defaults to true.

Increases the scratch pad per logline from 512 to 2K.

Change-Id: I8935d10eae2496a2096a44f9f10d89585a48ae8c
Handle "Var: Val" with empty " Val"s.

Change-Id: I38980e81f6df32ee553695cf6998c80af1f69883