Remove support for deprecated repos

[brody4hire]

For example: remove references to amazon-fireos, bada, blackberry, ubuntu, firefoxos, qt, tizen, webos, wp8 platforms from sources such as:

• src/platform-release.js
• src/repo-update.js
• src/repoutil.js
• src/versionutil.js
• test/flagutil.test.js

Need to investigate if any other packages may be deprecated.

related: https://github.com/apache/cordova-mobile-spec/pull/148