redistributePar with numberOfSubdomains 1 in decomposeParDict

Running cht cases with in decomposeParDict:

regions
{
    heater
    {
        numberOfSubdomains  1;
    }
}

conflicts with the old way of doing reconstruction through this method. In earlier versions of redistributePar we used numberOfSubdomains = 1 to indicate reconstruction mode. Now there is a -reconstruct option.

Choices:

• recognise multi-region cases and don't switch on reconstruction mode if numberOfSubdomains 1
• do not use numberOfSubdomains setting to indicate reconstruction mode

@mark