- Refrain from calling asIntern() from within substring()
# See xp-framework/xp-framework#63, thanks @pdietz, you pushed my
# attention in the right direction! Not the object creation is so
# expensive, the (useless) conversion is.
# Before: 0m1.299s, after: 0m0.952s
Merge pull request #265 from thekid/substr-performance

String::substring() performance
- MFU