Revert "Require Ruby >= 1.9.3"

This reverts commit e18fff0b34379fc8111eaf938e12550d11b9b3d5.

Conflicts:
	.travis.yml
Fix gem bundle so it can be installed under Ruby 1.9.2
Revert "Add Ruby 2.0.0 to the Travis matrix"

This reverts commit d25a121188d0d793559c66489c4d55dea4774a64.

Conflicts:
	.travis.yml