Reading From Modbus Should Not Block Other Channels

[jacobson3]

When validating channels, we check both directions (reading and writing) when searching for overlaps but we should only check for overlaps between channels writing to Modbus registers/coils.

We should be able to allow this by editing "validate line configuration.vi" to check for overlaps only if we are writing. We would also need to check the runtime class under "process mappings.vi" to make sure this wouldn't effect the runtime behavior.