'''Problem:''' it doesn't

A version number is:

   join $listOfNonNegativeIntegers .

Want to add recognition of things like ''8.4b1''

'''Concept:''' allow values -1 and -2 in the list.

Wherever the result has ''.-1.'' replace with ''b''

Wherever the result has ''.-2.'' replace with ''a''

'''Implies:''' ''a'' or ''b'' can't be next to a ''.''

''a'' or ''b'' can't be first or last char in version number

Things like ''1.2a5b3.7'' are OK (if weird)

'''Specification:'''

[[package vcompare]] extended obvious way (-2 < -1 < 0).

[[package vsatisfies]] -- need to specify sensible rules 
(for itself and to be used by [[package require]])

[[package vsatisfies 1.1 1.0]] => 1

[[package vsatisfies 1.1a0 1.0]] => 1

[[package vsatisfies 1.1b0 1.0]] => 1

'''Note:''' implies responsibility for controlling
package availability placed on package installer!
(Provide alpha/beta releases to developers, but hide
from end-users, for example -- special TCLLIBPATH, etc.)

[[package vsatisfies 1.1a1 1.1a0]] => ???

[[package vsatisfies 1.1b0 1.1a0]] => ???

[[package vsatisfies 1.1 1.1a0]] => ???

[[package vsatisfies 1.1b1 1.1b0]] => ???

[[package vsatisfies 1.1 1.1b0]] => ???

Also consider new cases when [package BoF: PACKAGE REQUIRE support for RANGES of acceptable versions] is present.

Also consider new cases when
[package BoF: PACKAGE REQUIRE support for RANGES of acceptable versions] is present.

[['''package vsatisfies''' ''$version $range ?$range ...?'']]