Fix YAML colour schemes to be Psych readable

Trying to load originals with Psych:
[ytti@lintukoto ~]% pry -r yaml
[1] pry(main)> YAML.load_file "/home/ytti/tmp/keybox/resources/light_bg.color_scheme.yaml"
Psych::SyntaxError: (/home/ytti/tmp/keybox/resources/light_bg.color_scheme.yaml): did not find expected node content while parsing a flow node at line 19 column 19

Using 'Syck' same file works just fine. However in Ruby2.0 you cannot
switch to Sych anymore, but you have to use Psych.
Update to fix me for project management
remove setting the yaml engine specifically
convert from RSpec to minitest spec
remove -w code
uncomment the tests
switch to psych serialization
fix spec that made no sense
remove warnings
bump version
test the other direction
clean up spec warnings
force ruby 1.9.3