IOS-2794 Revert "Make that a mutable array"

This reverts commit 514cc4b23c.

PantomimeFramework/PantomimeFramework/NSData+Extensions.h

@@ -255,7 +255,7 @@
   @result An instance of NSArray holding all components. The array is
           empty if the separator was not found in the receiver.
 */
-- (NSMutableArray *) componentsSeparatedByCString: (const char *) theCString;
+- (NSArray *) componentsSeparatedByCString: (const char *) theCString;
 
 /*!
   @method asciiString

pantomime-lib/Framework/Pantomime/CWPart.m

@@ -553,7 +553,7 @@ static int currentPartVersion = 2;
         dataToSend = [dataToSend wrapWithLimit: limit];
     }
 
-    NSMutableArray *allLines = [dataToSend componentsSeparatedByCString: "\n"];
+    NSArray *allLines = [dataToSend componentsSeparatedByCString: "\n"];
     NSUInteger count = [allLines count];
     for (int i = 0; i < count; i++) {
         if (i == count - 1 && [[allLines objectAtIndex: i] length] == 0) {

pantomime-lib/Framework/Pantomime/NSData+Extensions.m

@@ -734,7 +734,7 @@ static const char *hexDigit = "0123456789ABCDEF";
   return NSOrderedDescending;
 }
 
-- (NSMutableArray *) componentsSeparatedByCString: (const char *) theCString
+- (NSArray *) componentsSeparatedByCString: (const char *) theCString
 {
   NSMutableArray *aMutableArray;
   NSRange r1, r2;