refactor: prepare for boolean functions

* Defines a BooleanT type
  * adds options to the Type constructor, so far just to allow conversions
    from other types
  * renames Number type to NumberT
  * records the name of types, and puts the name in the string representation
  * defines a conversion fron BooleanT to NumberT, specified to be automatic
  * stub code for automatic conversions, not yet complete
  * BooleanT not yet added to nanomath

Checked that the new facilities do not disrupt the prior behavior on numbers.

src/number/__test__/NumberT.spec.js

@@ -0,0 +1,11 @@
+import assert from 'assert'
+import {NumberT} from '../NumberT.js'
+
+describe('NumberT Type', () => {
+   it('correctly recognizes numbers', () => {
+      assert(NumberT.test(3))
+      assert(NumberT.test(NaN))
+      assert(NumberT.test(Infinity))
+      assert(!NumberT.test("3"))
+   })
+})