Allow exponents to use "D+XX" or "D-XX" number format.

Fixes PR#686 with MOLPRO Molden files.

Change-Id: Ib91d3c17449b57ce4212a4499e25bbafb17bfe97
Merge topic 'FIX_read-molpro-molden' into master

c666de6a Allow exponents to use "D+XX" or "D-XX" number format.