BuildQueryString is an internal function to be used by request methods in individual resource packages.

It accepts a tagged structure and expands it into a URL struct. Field names are converted into query parameters based on a "q" tag. For example:

type struct Something {
   Bar string `q:"x_bar"`
   Baz int    `q:"lorem_ipsum"`

instance := Something{
   Bar: "AAA",
   Baz: "BBB",

will be converted into "?x_bar=AAA&lorem_ipsum=BBB".

The struct's fields may be strings, integers, or boolean values. Fields left at their type's zero value will be omitted from the query.