[Draft] refactor Entitize method, use HtmlEncode, add unit tests

[EvgeniyZ]

proposal with fix for #323

@JonathanMagnan hi there, can you please take a look at changes for Entitize method. I'm strongly suggesting use standard System.Net.WebUtility.HtmlEncode method for entitize unicode characters.
If it looks OK, I can improve DeEntitize method, just use System.Net.WebUtility.HtmlDecode method instead of complicated logic. Also I think it's really useful to get rid off _entityName, _entityValue dictionaries.
I'm aware of entitizeQuotAmpAndLtGt parameter and wasn't sure when we should ignore entitize these characters

[JonathanMagnan]

Hello @EvgeniyZ ,

We will look at it, thank for the pull ;)

What I'm the most afraid with this change is the backward comaptibility but perharp everything is perfect.

Best Regards,

Jonathan

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[JonathanMagnan]

Hello @EvgeniyZ ,

The latest version contains your code.

However, you need to turn the option UseWebUtility on to make it works: https://github.com/zzzprojects/html-agility-pack/blob/master/src/HtmlAgilityPack.Shared/HtmlEntity.cs#L27

The reason is for backward compatibility. In the past, we did some similar change which we have to rollback since people reported us some issues in their code.

Let me know if everything works as expected.

Best Regards,

Jonathan

[escobar5]

I am using Entitize to convert all special characters in an html to their respective entities, if I set UseWebUtilty = false, Entitize doesn't encode my html tags as I expected, so for example

HtmlAgilityPack.HtmlEntity.Entitize("<span>é</span>")

would return <span>&eacute;</span>

but if i set UseWebUtilty = true, then, the same call returns <span>é</span>

I need the html intact as per the first example, the problem I have with UseWebUtilty = false is that some emojis are not encoded correctly as stated in #323