Write forces and velocities to compressed TNG.

Write forces and velocities to compressed TNG.

If there is no uncompressed coordinate output write forces
and velocities to the TNG file with compressed coordinate
output. If there is uncompressed coordinate output to a
TNG file forces and velocities will be written to it.

Use a greatest common divisor to set the frequency of some TNG
data output to ensure lambdas and box shape are written at least
as often as anything else.

This commit closes #1863.

Change-Id: I61bb5513f5080847f9098ff4fd7f01c8d1415a8f