Add metric units to all documentation

Hey all,

it seems that the link above is broken, it leads to the wrong citation. The correct target is this one:

^ * In the United States, the history of legislation begins with the Metric Act of 1866, which legally protected use of the metric system in commerce. The first section is still part of US law (15 U.S.C. § 204).[k] In 1875, the US became one of the original signatories of the Metre Convention. In 1893, the Mendenhall Order stated that the Office of Weights and Measures … will in the future regard the International Prototype Metre and Kilogramme as fundamental standards, and the customary units — the yard and the pound — will be derived therefrom in accordance with the Act of 28 July 1866. In 1954, the US adopted the International Nautical Mile, which is defined as exactly 1852 m, in lieu of the US Nautical Mile, defined as 6080.20 ft = 1853.248 m. In 1959, the US National Bureau of Standards officially adapted the International yard and pound, which are defined exactly in terms of the metre and the kilogram. In 1968, the Metric Study Act (Pub. L. 90-472, 9 August 1968, 82 Stat. 693) authorised a three-year study of systems of measurement in the US, with particular emphasis on the feasibility of adopting the SI. The Metric Conversion Act of 1975 followed, later amended by the Omnibus Trade and Competitiveness Act of 1988, the Savings in Construction Act of 1996, and the Department of Energy High-End Computing Revitalization Act of 2004. As a result of all these acts, the US current law (15 U.S.C. § 205b) states that
It is therefore the declared policy of the United States –

  1. to designate the metric system of measurement as the preferred system of weights and measures for United States trade and commerce;

  2. to require that each Federal agency, by a date certain and to the extent economically feasible by the end of the fiscal year 1992, use the metric system of measurement in its procurements, grants, and other business-related activities, except to the extent that such use is impractical or is likely to cause significant inefficiencies or loss of markets to United States firms, such as when foreign competitors are producing competing products in non-metric units;

  3. to seek out ways to increase understanding of the metric system of measurement through educational information and guidance and in Government publications; and

  4. to permit the continued use of traditional systems of weights and measures in non-business activities.