Stop exporting CRLF and SEPARATOR

[emersion]

These are internal V1 details, users of this package shouldn't need
them.

Closes: #29

[coveralls]

Coverage remained the same at 91.222% when pulling 1a07500 on emersion:unexport-internal into fbefd10 on pires:master.

[emersion]

Notes:

• I wonder if we should unexport SplitTLVs too. Is there a case where users would get raw TLVs and want to split them?
• The SIGV1/SIGV2 variables are left exported because some users might want to manually recognize PROXY headers.

[pires]

* I wonder if we should unexport `SplitTLVs` too. Is there a case where users would get raw TLVs and want to split them?

There are cases, yes. One example is https://github.com/pires/go-proxyproto/blob/master/tlvparse/ssl.go#L96. Users may have their own code that requires this.

* The `SIGV1`/`SIGV2` variables are left exported because some users might want to manually recognize PROXY headers.

Yep!

[pires]

Thank you very much for your contribution.

[emersion]

Users may have their own code that requires this.

Ah, I see, makes sense then!