Benchmarker/MainForm.cs: fix Benchmarker cause a crash if its open & closed, then joined a game & download something (mod/game)
(Timer keep running in background even if Benchmarker was closed. Needed Dispose())
BattleBar.cs: found 1 timer that could be safely disposed off
Merge pull request #182 from xponen/zkl_benchmarker_timer_crash

ZKL: fix downloader won't work when closed Benchmarker