Simplify output of the forces functionObject

Functionality to add/problem to solve

The output produced by the forces function object is much more complex than what it could be. For each time step the output line is as

0.65004 \t(4.966426e-01 1.252274e+00 -3.007485e-04)\t(4.246068e-01 1.273820e+00 2.141011e-17)\t(7.203576e-02 -2.154636e-02 -3.007485e-04) Here \t is a tab. Also, two separate files are created, one for the forces and one for the moments.

Proposal

Simply having 10 values separated by spaces or tabs (consistently!) would make it much easier to open the text file with e.g. numpy or pandas, without sacrificing much. Combining both forces and moments into single file is also reasonable. A switch could be added to allow falling back to the old output format.

## Reattaching the author to the issue ticket: @timofeymukha ##