(maint) Fix cmake find scripts to be consistent with other conventions.

Fixing the use of uppercase statements and spacing in find scripts to be consistent with other files.
(maint) Replace scalar value types with scalar_value<T>.

Replacing string_value and integer_value with tempalted scalar_value<T> class.
Adding boolean_value which is a typedef for scalar_value<bool>.
(CFACT-23) Implement YAML output.

Note: this commit adds a new dependency on yaml-cpp.

Implementing YAML output with the addition of a --yaml (-y) command line
option.
Merge pull request #37 from peterhuene/feature/yaml

(CFACT-23) Implement YAML output.