newlines in values are wrongly escaped

[hupfdule]

Newlines in values result in a double backslash before the newline when calling PropertyFile#update(). However, there should be only one.

For example calling

propertyFile.set("mykey", "my value \nwith newline");

should result in

mykey = my value \
with newline

but is actually written as

mykey = my value \\
with newline