set validation: validate as fine if we have null instead of iterable

Rationale: now I can skip/abort the validation conditionally such as with the
following:

  in: ->
    if @get('country') == 'CA'
      ['ON', 'QC', 'NS', 'NB', 'MB', 'BC', 'PE', 'SK', 'AB', 'NL', 'NT', 'YT', 'NU']
    else
      null
Update ROADMAP.md

0.4.3 is complete, Windows is fully supported.
Merge pull request #359 from TheHydroImpulse/patch-1

Update ROADMAP.md
Solve Issue 337
Solve issue 337
Issue #367. Set chai.Assertion.includeStack = true to show assertion failure line numbers.
Merge pull request #368 from btbinhtran/issue367

Issue #367
Update packages/tower-middleware/server/agent.coffee

fix exception:
TypeError: Object Mac OS X 10.8.2 has no method 'match'
    at Object.Tower.MiddlewareAgent [as handle] (/home/erundook/towertest/node_modules/tower/packages/tower-middleware/server/agent.coffee:14:23)
Merge pull request #376 from erundook/patch-1

fix agent detection bug: TypeError: Object Mac OS X 10.8.2 has no method 'match'
bug fix
Merge pull request #362 from vraptor75011/master

use any model name present in window DOM
Merge pull request #350 from tremby/set-validator

set validation: validate as fine if we have null instead of iterable
Locked package versions for tower packages and new app packages
Merge pull request #392 from btbinhtran/proper-package-versioning

Locked package versions for tower packages and new app packages
0.5.0
add list of repos for dev
readme
readme
readme
note about alpha-ness