gnu: units: Update to 2.02.

* gnu/packages/maths.scm (units): Update to 2.02.

Merge branch 'master' into core-updates

gnu: pspp: Update to 0.8.1.

* gnu/packages/maths.scm (pspp): Update to 0.8.1.

Merge branch 'master' into core-updates

gnu: gsl: Disable numerically unstable test on i686.

* gnu/packages/maths.scm (gsl): Disable test.

gnu: gsl: Move from module algebra to maths.

* gnu/packages/algebra.scm (gsl): Move variable from here...
* gnu/packages/maths.scm (gsl): ...to here.

gnu: Add pspp.

* gnu/packages/maths.scm (pspp): New variable.
* THANKS: Thank John Darrington for help with debugging.

gnu: Add units.

* gnu/packages/maths.scm: New module.
* gnu-system.am (GNU_SYSTEM_MODULES): Add module.