change sampling method for more efficiency fixes #20
off by about a factor of 2; only do fida_chord xor npa_chord
check to see if fbm is allocated when moving a gyrorbit away to prevent segfault; still off by factor of 2
fix factor of 2; only doing cells that contribute to detector can only be done for npa because when a fast ion neutralizes it travels and then emits light. light is not guaranteed to come from the cell which the fast ion was neutralized
use guided scheduling for more efficient use of cores
Merge pull request #24 from D3DEnergetic/new_sample

Close issue #20, overall performance increases