remove Null Transport

[michalbundyra]

since composer.json master branch is only support php:^7.1

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Originally posted by @samsonasik at zendframework/zend-mail#195

[michalbundyra]

Please rebase this against develop and change the target branch. Since it's a BC break, it needs to target a new major version.

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Originally posted by @weierophinney at zendframework/zend-mail#195 (comment)

[michalbundyra]

@weierophinney I've rebased against develop and change target to develop branch.

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Originally posted by @samsonasik at zendframework/zend-mail#195 (comment)

[michalbundyra]

i suppose it addresses problem that null is no longer allowed as class names in newer php versions?

and explanation why it's removed not just renamed?

also, fix spelling: Tranport -> Transport,

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Originally posted by @glensc at zendframework/zend-mail#195 (comment)

[michalbundyra]

the null transport was mapped to inMemory, so, it is same to use inMemory. Thank you, I've updated PR title Tranport -> Transport,

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Originally posted by @samsonasik at zendframework/zend-mail#195 (comment)

[michalbundyra]

This repository has been moved to laminas/laminas-mail. If you feel that this patch is still relevant, please re-open against that repository, and reference this issue. To re-open, we suggest the following workflow:

• Squash all commits in your branch (git rebase -i origin/{branch})
• Make a note of all changed files (`git diff --name-only origin/{branch}...HEAD
• Run the laminas/laminas-migration tool on the code.
• Clone laminas/laminas-mail to another directory.
• Copy the files from the second bullet point to the clone of laminas/laminas-mail.
• In your clone of laminas/laminas-mail, commit the files, push to your fork, and open the new PR.
  We will be providing tooling via laminas/laminas-migration soon to help automate the process.

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Originally posted by @weierophinney at zendframework/zend-mail#195 (comment)

[samsonasik]

I've created PR #98 for it.