helper functions for deleting IA_PD and IA_Prefix options; all prefixes from received REPLY are checked whether they are valid
validating all prefixes from received answer for SOLICIT message.
Merge branch 'plural_prefix_validation' of git://github.com/macfij/dibbler into macfij-plural_prefix_validation

Conflicts:
	ClntMessages/ClntMsgSolicit.cpp
Merge branch 'macfij-plural_prefix_validation'

Conflicts:
	CHANGELOG