skip these for now
Benchmarking and some improvements

LogplexLineFormatter benchmark
1072 B/op -> 1046 B/op
Some caching and stuff

From this:
BenchmarkLogplexLineFormatter 5000000      3326 ns/op    1046 B/op
14 allocs/op

To this:
BenchmarkLogplexLineFormatter10000000      2050 ns/op     852 B/op
6 allocs/op