Named attachements

[Sata51]

Add the ability to attach a file with a custom file name Instead of using the default:

e := NewEmail()
e.AttachFile("test.txt")

you can provide a custom named file using this:

e := NewEmail()
e.AttachFileWithName("internalName.txt", "publicName.txt")

[jordan-wright]

Hi @Sata51,

This LGTM but could you do me a favor and add a test that confirms the behavior is working as expected?

Thanks!

[Sata51]

I've done it :D

[NoelHG]

I was about to push a branch with this exact change. It's pretty essential since most files on servers have crazy names with timestamps lol

[Fank]

@jordan-wright could you may take a look at this again?

[Fank]

@Sata51 could you fix the conflicts?

[Sata51]

@Fank fixed