Add creation of options hash to Hwacha::Config

Instead of putting data fields into Hwacha::Config and then pulling them
out by name, this new options method will allow us to have the
configuration object be responsible for giving us back the set options
as a configuration for Typhoeus.
Use Hwacha::Config #options to initialize Typhoeus

Instead of pulling out set configuration variables one by one from
Hwacha::Config we now just ask Hwacha::Config to output its set options
for Typhoeus.

This change involved a bit of code movement in Hwacha. Instead of
manipulating a max_concurrent_requests instance variable we now just
deal with the Hwacha::Config object directly.

The Hwacha#check method is also no longer responsible for knowning how
to build the hydra object. Hwacha#build_hydra now handles all that
setup.

The specs are slightly redundant in that we check that Hwacha
initialization sets variables on the configuration object correctly and
also check that the configuration object sets the correct option in
Typhoeus::Hydra. Arguably we could only spec that the correct option is
set in Typhoeus::Hydra when the correct configuration variable is set.
Those extra specs are from when I was building out the configuration
object capability and I may just delete them soon.
0.3.0: initialize Hydra using configuration object
Merge branch 'use-hwacha-config-to-initialize-typhoeus'