Marking static factories as deprecated

[weierophinney]

As requested in #175

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Originally posted by @boesing at zendframework/zend-cache#176

[weierophinney]

Need to add the new StorageFactory to the ServiceManager configuration. Reminder for myself.

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Originally posted by @boesing at zendframework/zend-cache#176 (comment)

[weierophinney]

Well, it looks like the pcntl_fork unit test for Filesystem fails in travis for PHP 7.2 lowest dependencies.
I am on PHP 7.2 locally and the unit tests wont fail. Any suggestions?

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Originally posted by @boesing at zendframework/zend-cache#176 (comment)

[weierophinney]

Most likely unrelated to your changes

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Originally posted by @Ocramius at zendframework/zend-cache#176 (comment)

[boesing]

Done with #50, #118