Gem install test should use 'rake install'.

Was installing with 'bundle exec rake install'
Reproduce 'minitest' problem by calling 'version'

$ calabash-ios version will reproduce.
Reproduce 'minitest' problem when exiting console

$ calabash-ios console
> exit
Snap! Error! :(
Fixes minitest bug; don't include Test::Unit::Assertions

It appears that we don't use any Test::Unit::Assertions?
Changelog needs 'breaking change' text [skip ci]
Updates changelog w/ minitest PR

Also forces a merge test on Travis CI.
Merge branch 'master' into feature/fix-minitest-problem

Conflicts:
	script/ci/travis/install-gem-ci.rb
Merge branch 'feature/fix-minitest-problem'