Standard wire sizes - allow metric designs to access US sizes and US to access metric

[grumpyinca]

Currently, metric-unit designs have access to only metric standard wire sizes; US-unit designs have access to only US standard wire sizes. Also, the connection between wire diameter and tensile strength is significantly decoupled from standard wire sizes.

Note that with US units, there are different standard wire size tables for the different materials. This is not the case with metric standard size tables.

It would be an improvement if the concept of standard wire sizes could be expanded to include the standard sizes of the other unit system. For example, when operating on a metric design, the user should be able to select the metric equivalent of a US standard wire size. While this would be best accomplished by code changes, it is possible that an interim solution could be implemented with only documentation changes. Specifically, the Calculator View dialog for selecting a standard wire diameter (Edit Independent Variable Wire_Dia; SymbolValueWireDia.jsx) Help button could be directed to a cascade of Help pages that provide tables of both US and Metric values. Perhaps the tables could be merged. For example:

Material = Music Wire

US - inches	metric - mm		Type
0.105	2.667		1
0.106	2.692		2
0.1061	2.7		0
0.109	2.769		1

Type field key:
null (empty) - undefined
blank or non-numeric - undefined
0 - metric
1 - US 1st Preference
2 - US 2nd Preference

When rendered in the docs, shading could be used to better distinguish US and metric entries.

Tensile strength and all the other material properties could be included. Need to allow for identical materials (with differing wire size availability) from different wire vendors. Need to incorporate ASTM and Fed-Spec information, comments like source information.

Note that multiple other (currently) open issues touch on various aspects of selecting standard wire diameters. See:
#886
#873
#864
#584
#567 (--> #467, #456, #500, #504)