A for effort TK. Mark 13 does say that wars will continue, and even be worse than at that time (the beginnings of the sorrows), it does not condone it, it says that "ye shall be brought before rulers and kings for my sake, for a testimony against them."

As far as the centurion in Matthew, the point is not that Jesus condones war or violence, it is that Jesus loves all of us, irregardless of who we are. Even if you are a man that has soldiers beneath you. I've mentioned this on another post a little while back. With Christ all can be forgiven. Same goes for the passage in Acts. The point was that the gift of the Holy Ghost fell on a Gentile. I think during this period, centurions where about as common as cab drivers in New York City, Israel was an occupied nation.

Here's one or two for further consideration, if you truly beleive that Christ has called on his disciples to kill other people:
Peter 3:11 "Let him eschew evil, and do good; let him seek peace, and ensue it."
Luke 3:14 "And the soldiers likewise demanded of him, saying, And what shall we do? And he said unto them, Do violence to no man, neither accuse any falsely; and be content with your wages."