Change Equals() to only compare Value.

[aalmada]

This is a follow up on #30 that suggests changing Equals() and GetHashCode() to only compare Value. Advantages are explained in the issue description.

This PR also contains the following:

• Adds TryFromName() and TryFromValue() methods. These allow searching without exceptions thrown, improving considerably performance.
• Adds a ignoreCase parameter to FromName() and TryFromName(). The defaut value is trueto not break previous contract but, this is not the usual default value for this option and has considerably worst performance.
• Adds unit test for equals operations.
• Adds benchmarking project with option to benchmark equals or search operations.

Equals Benchmarks

The performance much better than for current master branch or even with changes proposed in #26 .

Search Benchmarks

The use os dictionaries make all search operations to have O(1) complexity. The use of exception is considerably slower than TryFromName() and TryFromValue() that are actually faster when value is invalid than when valid. Case sensitive searching is faster than when casing ignored.

[aalmada]

The benchmarks of current master branch for reference:

[ardalis]

Looks good - can you re-open?

[ardalis]

FYI, here's one place where I previously commented. @aalmada

Trying to find where you referenced the slides since I thought I replied there as well. In any case, the slide deck looked like a great presentation.