Updated default CanonicalizeIP output for IPv6 input. bnc837517

When CanonicalizeIP is invoked with IPv6 input it returns empty NETMASK.
NETMASKs are not used in IPv6 world that much. Moreover
Netmask::FromBits uses IPv4 specific implementation.
Modified Netmask::FromBits for longer prefixes

Do not try to handle non IPv4 prefixes.
Updated changelog.

Conflicts:
	VERSION
	package/yast2.changes
Created infrastructure for new testsuite in library/network.
Updated testsuite for CanonicalizeIP.

Ported existing tests from old testsuite into new one and added testcase
based on bnc#837517
Updated and ported testsuite for Netcard

Conflicts:
	library/types/test/Makefile.am
Merge remote-tracking branch 'upstream/master'

Conflicts:
	VERSION
	library/types/test/Makefile.am
	package/yast2.changes