Add get_value method to SimpleConfig

Add the get_value method to SimpleConfig, which allows the user
to get a value from a configuration file. Add tests for this
method.
Put get_value tests into their own file

Move the tests of the SimpleConfig get_value method into a new
file, simple_config_spec.rb
Add has_path method

Port the has_path method in the SimpleConfig class from the
Java HOCON library.
Add with_value method to SimpleConfig

Port the with_value method in the SimpleConfig class from
the Java HOCON library.
Add ConfigValueFactory

This commit adds a basic implementation of the ConfigValueFactory
class. This class contains only one method, with_any_ref, which
takes an object and transforms it into a ConfigObject.
Fix requires in ConfigValueFactory

Fix the require statements so that ConfigValueFactory can be
required without requiring other files.
Add "add" method to TokenWithComments

Port the "add" method to the TokenWithComments class.
Add at_key and at_path methods

Port the at_key and at_path methods from the Java HOCON library
into the AbstractConfigValue class.
Add without_path method

Port without_path method from the Java HOCON library into the
SimpleConfig class.
Fix ConfigImpl bug and add more tests

Fix bug in ConfigImpl wherein a boolean would be converted into
a ConfigBoolean with value true even if the boolean is false.
Increase test coverage for ConfigValueFactory tests by adding
a test to ensure this bug is no longer happening, and increase
test coverage of SimpleConfig spec tests by ensuring that
data structures can be added to a config.
Move requires into Hocon module

Move requires for all files in the Hocon module into
the module itself to eliminate uninitialized constant errors.
Remove commented line

Delete commented constant in the Path class that was no longer
needed.
Merge pull request #12 from fpringvaldsen/add-methods-for-puppet

Add methods required for puppet .conf module