Basic implementation of a mutable MediaType
Moving the immutable implementation into its own
file
Alright. Pretty much re-doing that entire experiment.
Separating the mutable and immutable into separate packages just created
a lot of unnecessary headache with cyclic dependencies... so I'm out.
Whooops. I was operating on a nil pointer before...
Adding the missing piece from the full type characters
Splitting up the tests
Adding a new test
Making sure to handle the edge-cases
More tests
Fixing the `FullType()` method based on the tests
New `Immutable()` method and test
New tests for the immutable struct
Now returning an explicit type in `Immutable()`
More tests!
The MediaTypeImmutable struct no longer contains a
pointer to a mutable struct. Containing a pointer was unnecessary and
dangerous, as it allowed the contained element to be modified outside
if not careful... breaking the immutability promise
Updating the `README.md` to show the new mutable
and immutable examples
Updating comments based on the `golint` rules
Renaming the mutable and immutable structs based on
the `golint` recommendation:

- MediaTypeMutable -> Mutable
- MediaTypeImmutable -> Immutable
Merge pull request #1 from Rican7/feature/mutable-and-immutable

Feature - Mutability and Immutability