normalizeEmail improvements

[ItalyPaleAle]

This patch contains multiple improvements to the normalizeEmail function. In particular:

• Includes support for normalizing other common email providers beside GMail: iCloud (incl. MobileMe), Outlook.com (including Windows Live and Hotmail) and Yahoo Mail. For example, allows stripping sub-addresses ("[email protected]" -> "[email protected]"), transformation of the local part to lowercase (as they're known for being case insensitive), etc
• Offers more granular options, for example letting users disable transformations that were before always applied

Previous options passed to "normalizeEmail" have been removed:

• "lowercase", which was only considered for non-GMail addresses, has been replaced with "all_lowercase" (applies to all addresses when "true") and "*_lowercase" (for each provider), offering more granular control
• "remove_dots", which before applied only to GMail, was renamed to "gmail_remove_dots" so it's clearer it's limited to GMail (no other provider does to same, to my knowledge)
• "remove_extension" which before applied only to GMail was replaced with "*_remove_subaddress" for all providers that support it (GMail, iCloud and Outlook.com use the + symbol; Yahoo uses -). The word "subaddress" is also more appropriate to describe them - that's how they're called, for example, on Wikipedia
• A new option has been added to enable/disable the @googlemail.com to @gmail.com conversion

When running without options, the behaviour of this function is almost identical to before (except that now subaddresses are removed for more providers and not just GMail). However, I was not able to make this patch fully backwards-compatible, meaning that I was not able to ensure that the same results would come out with supporting the same legacy switches (I tried!). Because of that, "legacy" switches (such as "remove_dots") have simply been removed, and this patch is partly backwards-incompatible. However, I do strongly feel that it's a necessary step in the right direction, to allow adding more providers in the future in a coherent way.

PS: It's been a while since I submitted you PR's... Nice to be back :)

[coveralls]

Coverage decreased (-0.2%) to 98.882% when pulling c047210 on EgoAleSum:email-patch into 3266767 on chriso:master.

[coveralls]

Coverage decreased (-0.2%) to 98.882% when pulling 309a530 on EgoAleSum:email-patch into 3266767 on chriso:master.

[coveralls]

Coverage increased (+0.02%) to 99.14% when pulling e12cd97 on EgoAleSum:email-patch into 3266767 on chriso:master.

[chriso]

Thanks, looks good! I won't merge this one just yet; I'll push it through as v6 with some other breaking changes.

[ItalyPaleAle]

Thanks, what is the timeframe for v6?

[chriso]

@EgoAleSum hoping to have it out this week.