Merge: Faster scan in the loader

Merge: Faster scan in the loader

Some people experienced a slowdown in nitls and nitpick since the last changes in the loader.

The culprit where mostly expensive services on strings and filepaths. see #1736
This PR improves the current state of affairs by using less expensive services or rearrange them.

For `time nitls -pt ../contrib/ ../lib ../examples/`

Before:
* real	0m2.159s
* user	0m1.840s
* sys	0m0.288s

After:
* real	0m0.545s (-75%)
* user	0m0.352s (-81%)
* sys	0m0.172s

Pull-Request: #1737
Reviewed-by: Alexis Laferrière <alexis.laf@xymus.net>