O(N^2) when calling PropertiesEditor .insert() N times

[InPermutation]

Related to #16, my Lambda is still timing out on that ≤1000 lines x ≤400 characters file.

I have read my profiler output more carefully, and found what I think is the core performance issue: PropertiesEditor calls this.parseLines() on every .insert() call.

On the first insert, parse the first line.
On the second insert, parse the first and second lines.
On the third insert, parse the first, second, and third lines.
…
On the Nth insert, parse lines 0...N.

This is Shlemiel the painter's algorithm.

I would submit a PR, but I'm not yet sure what the right approach is to fixing this. (Maybe an intermediate PropertiesBuilder that only parses at the end?)

WORKAROUND: Since I am not editing a .properties file, but rather generating a brand new one, I can avoid PropertiesEditor, and instead just linearly generate my own output, using the functions in properties-file/escape.

[nbouvrette]

@InPermutation I implemented lazy parsing which is now available in version 3.3.3

I think in a scenario where you want to do multiple inserts performance will be a lot better. Let me know if you see anything I might have missed.