Fix: make sorting of servers a bit more robust (#16)
This fixes a few issues:
- if a patchpack had a version > "1.10", it would show up on top
of the list. This is solved by adding a "priority", where
official servers get the highest priority, patchpacks the second,
and everything else the lowest.
- custom builds of JGRPP are like "jgrpp-0.38.1-39-g1234"; the
old code tried to convert "1-39-g1234" to a number (and failed).
This is now solved by only considering "0.38.1" as numeric values.
- to avoid future issues, only consider "A.B.C" as "major.minor.patch"
if all three are numeric.
