String processor

One of C.T.Co Java school projects.
It removes newline character preceded by n>=1 backslash characters. No regexp.

Examples:

1. In: "abc\\\ndef"
   Out: "abcdef"

2. In: "abc\\\\\ndef"
   Out: "abcdef"

3. In: "abc\ndef"
   Out: "abc\ndef"

4. In: "abc\\def"
   Out: "abc\\def"