Add Support for BitVector and BitMatrix Indexing

Fixes #707.

Author: RoyiAvital

test/test_atoms.jl

@@ -520,6 +520,15 @@ function test_IndexAtom()
     y = [true, false, true]
     x = Variable(3)
     @test string(x[y]) == string([x[1], x[3]])
+    target = """ 
+     variables: x1, x2, x3 
+     minobjective: [1.0 * x1, 1.0 * x3] 
+     """ 
+     _test_atom(target) do context 
+         x = Variable(3)
+         y = BitVector([true, false, true])
+         return x[y] 
+     end
     return
 end