[boost] pqs_3_0_2 available in the Boost.Vault

pqs_3_0_2, the next version of physical_quantities library proposal for boost, is available in the vault in Physical Quantities Units directory. This version has much improved compilation speed typically (say) 4 seconds as opposed to 30 for pqs_3_0_1. (pqs_3_0_1 is still available for comparison purposes). Little or no documentation as yet, but useage is relatively straightforward as I hope can be gleaned from files in the libs/pqs/examples and libs/tpqs/test directories. I hope to get down to writing proper documentation for the library next. regards Andy Little