Move probing logic to control module

Author: clarfonthey

src/control/mod.rs

@@ -1,10 +1,12 @@
 mod bitmask;
 mod group;
+mod probe;
 mod tag;
 
 use self::bitmask::BitMask;
 pub(crate) use self::{
     bitmask::BitMaskIter,
     group::Group,
+    probe::{Probe, ProbeItems},
     tag::{Tag, TagSliceExt},
 };