initializeMeshSubsets() across process vars and components.

MeshSubset initialization across all process variables and components.

Two small improvements/fixes

Reported by the clang sanitizer.

The counter k could be negative in case an empty line or comment line was read.

Set log level at runtime

See LogogSetup.h for possible values.
tests-target has a log level of warn.

Fix clang sanitizer issues

Multicomponent process variables and their output.

This removes the clang sanitizer error "runtime error: unsigned integer overflow: 0 - 1 cannot be represented in type 'size_type' (aka 'unsigned long')" in the test

Avoid warning/error/debug messages in SurfaceGrid

Adding new mesh properties reqiure non-const access.

Tetgen fix + tests