Use maps

[GeoffreyPS]

@abitdodgy,
See below for the updates to use Maps instead of HashDicts. There are a few other updates that exist outside of simply favoring the new data type:

Major Version bumped to 1.0

• If anyone is depending on this library and is expecting HashDicts, this library may break their code since many functions in the Counter module will return Maps.

Elixir Version 1.3 or higher required

• This bump is more to anticipate folding in the Soundex branch, but it's necessary to bump the version to anything >= 1.2 since HashDict is deprecated.
• The reference to Elixir Version 1.3 is included in the mix.exs and .travis.yml files.

Dialyxir added to development dependencies

• I needed to use Dialyzer to ensure the types were correct.
• Dialyxir only includes a couple of mix tasks to aid in running Dialyzer.
• It's probably a good idea to have typespecs included in the documentation on public functions at least.
• More info on Dialyxir

I think that's everything for bringing things up to date with removing the HashDicts. Please let me know if you thing anything else should get changed before merging it in.

[abitdodgy]

@GeoffreyPS I can't merge this. Apparently there are some conflicts. I'll have a look this weekend. I'm sorry about my tardiness, but I am in a whole different world at the moment.

[abitdodgy]

@GeoffreyPS I merged your soundex branch. This one has a conflict. I'm not sure what the deal is, but I'll try and get to it this weekend. I know I said that before, but I promise I'll get it done this time. 😀

[GeoffreyPS]

Thanks for looking into it. It has been a little while since I've thought about it, but I think it was about the Travis CI service needing to anticipate Elixir 1.3+ instead of 1.0.