In civil actions no witness shall be excluded because he is a party to the suit or interested in the issue to be tried. Provided, that in actions by or against executors, administrators or guardians in which judgment may be rendered for or against them, neither party shall be allowed to testify against the other as to any transactions with or statements of the testator, intestate or ward, unless called to testify thereto by the opposite party. Provided further, that this section may be amended or repealed by the General Assembly.