Raw path and IP parsing

[tzaeschke]

Fix and better testing for parsing of raw paths and IP addresses.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Files	Coverage Δ	Complexity Δ
src/main/java/org/scion/jpan/ScionUtil.java	96.51% <100.00%> (+2.12%)	30.00 <5.00> (ø)
...rc/main/java/org/scion/jpan/internal/IPHelper.java	100.00% <100.00%> (+57.69%)	19.00 <0.00> (+11.00)
...in/java/org/scion/jpan/internal/PathRawParser.java	65.85% <100.00%> (+5.35%)	13.00 <0.00> (+3.00)