Explicit initialization for previousEdge2 variable and check on number of iterations

previousEdge2 variable was not initialized (caused Run-Time warning in Visual Studio).
Added explicit initialization and helper variable for number of
iterations to only check previous edges after initial iteration.
Added check that all TargetSeedIds are found.
Merge pull request #94 from lantiga/master

Pulling Pieter Kitslaar's commits. Thanks!