Use Hashie::Dash for GenderizeIoRb Results

Lookng through the project history, caching was added first
followed by support for ActiveSupport caches

When ActiveSupport caches was added, the return value changed from ::GenderizeIoRb::Result
to a hash with {:result, :cache_db, :cache_as}

Corresponding spec file was not updated, so was failing when making calls to attributes on the returned hash

I'm not familiar with ActiveSupport caches so assume that the returned hash is necessary for the functionality

Updated the spec file so that tests pass

Found that the notation res[:result].name, etc... was confusing
so used Hashie so create objects: res[:result].name -> res.result.name

Found that Hashie was silently failing if an attribute was being called on the returned Hashie object

Change to Hashie::Dash so that the properties could be explicitly defined,
forcing Hashie to throw an error if accessing an undefined property

Replaced Hashie with SimpleDelegator

From PR review:

Requiring the gem Hashie to simply delegate methods in the ActiveSupport Cache result is overkill

Use SimpleDelegator to provide all methods on the hash + accessors for the object response

Use an array of accepted accessors so that it is easy to add or remove accessors as needed in the future

Did not extend class Hash since this can lead to unexpected behavior. See http://words.steveklabnik.com/beware-subclassing-ruby-core-classes for details
Handle multiple requiests simultaneously

Usage:

gir = GenderizeIoRb.new
gir.get_info_for_name(["name1", "name2", ...])

Returns:
{
	result: [GenderizeIoRb::Result, GenderizeIoRb::Result, ....]
	cache_db: @cache_db
	cache_as: cache_as_result (w/ populated array)
}

Raises Warning if name is not found

Note: Updated loading data from the cache
Passing existing specs
Did not write new specs for caching output from multiple requests
May break with using multiple requests with caching

Code gardening from PR Review

Removed unecessary calls to to_s

Used consistent indentation for case statements