Fix/missing zip with public declaration (#26)

* create tests to prove the error

* make all existing zip(with:) function public

* add zip2(with:)

Author: FredericRuaudel

Sources/Overture/ZipSequence.swift

@@ -162,7 +162,18 @@ public struct Zip3Sequence<
   }
 }
 
-func zip<
+public func zip<
+  A: Sequence,
+  B: Sequence,
+  C
+  >(
+  with f: @escaping (A.Element, B.Element) -> C
+  )
+  -> (A, B) -> [C] {
+    return { zip($0, $1).map(f) }
+}
+
+public func zip<
   A: Sequence,
   B: Sequence,
   C: Sequence,
@@ -174,7 +185,7 @@ func zip<
     return { zip($0, $1, $2).map(f) }
 }
 
-func zip<
+public func zip<
   A: Sequence,
   B: Sequence,
   C: Sequence,
@@ -187,7 +198,7 @@ func zip<
     return { zip($0, $1, $2, $3).map(f) }
 }
 
-func zip<
+public func zip<
   A: Sequence,
   B: Sequence,
   C: Sequence,
@@ -201,7 +212,7 @@ func zip<
     return { zip($0, $1, $2, $3, $4).map(f) }
 }
 
-func zip<
+public func zip<
   A: Sequence,
   B: Sequence,
   C: Sequence,
@@ -216,7 +227,7 @@ func zip<
     return { zip($0, $1, $2, $3, $4, $5).map(f) }
 }
 
-func zip<
+public func zip<
   A: Sequence,
   B: Sequence,
   C: Sequence,
@@ -232,7 +243,7 @@ func zip<
     return { zip($0, $1, $2, $3, $4, $5, $6).map(f) }
 }
 
-func zip<
+public func zip<
   A: Sequence,
   B: Sequence,
   C: Sequence,
@@ -249,7 +260,7 @@ func zip<
     return { zip($0, $1, $2, $3, $4, $5, $6, $7).map(f) }
 }
 
-func zip<
+public func zip<
   A: Sequence,
   B: Sequence,
   C: Sequence,
@@ -267,7 +278,7 @@ func zip<
     return { zip($0, $1, $2, $3, $4, $5, $6, $7, $8).map(f) }
 }
 
-func zip<
+public func zip<
   A: Sequence,
   B: Sequence,
   C: Sequence,