* bundle gem previously ignored gem.test when passed empty -t flag,
defaulting to RSpec
* bundle gem will now ask user for test framework when passed empty -t
flag and gem.test is set to false, but will not overwrite gem.test
* thor option parsing for String types falls back to human name for nil,
so setting lazy_default to nil won't work
* c5161501e0/lib/thor/parser/options.rb (L224)
Default to Bundler.settings["gem.test"] for empty --test
Add shared examples for test framework to newgem spec
Add examples for empty --test flag to newgem spec
Simplify conditional for prompting test framework
Follow naming conventions for bundler settings
Add more descriptive test framework help text for bundle gem
Update man pages for bundler
https://github.com/rubygems/rubygems/commit/ab0785a09f
