Added new sinusoidal source type.
Added geometric dimensions colorspinor::FieldOrder together with associated getter.
In BiCGstab, if preserve_source is false, then the redisual overwrites the source.
Reset mg parameters to block size 4x4x4x4 and MR smoother.
For free field testing we must use a color-independent source vector.
Added some sinusoidal testing to MG::verify().