Remove parameter EOLCharacterLength and detect it automatically

[jkrzefski]

Take a look at this line:

multipart-parser/src/StreamedPart.php

Line 157 in caad7d9

$partLength = $currentOffset - $partOffset - strlen($trimmed) - (2 * $eofLength);

I was wondering, why $eofLength had to be multiplied with 2. Then I realized, this was to necessary to remove the length of the delimiter plus the EOL after the delimiter plus the EOL in the previous line.

I realized, this could be an issue. When the EOL character length varies between the previous and the current line, this approach would fail. So I changed it to remove the length of $line instead of $trimmed, so the current EOL is already subtracted. Then I only have to subtract one $eofLength. But it must be the EOL character length of the previous line. So now, at the end of each iteration, I keep track of the EOL character length.

This entirely obsoletes the constructor parameter $EOLCharacterLength, because now it is fully dynamic. So, I removed this parameter. I no not see this as a breaking change as using excess parameters in object initialization does not fail and raises no warning.

I changed the tests accordingly, so they pass again. But to prove my point, I split my pull-request in two commits. The first commit removed the parameter for $EOLCharacterLength from the test-case testNoNewLineAtTheEndOfThePartsWhenNewLineIsOneCharacterLong. This makes the test fail. The second commit changes the implementation of StreamedPart and now the test passes again.