Add "related info" URLs to examples (#24)

* Added related info URL.

* Remove example related info links, we're not using them.

example/Podfile.lock

@@ -1,5 +1,5 @@
 PODS:
-  - CatalogByConvention (2.2.0)
+  - CatalogByConvention (2.3.1)
   - CatalogExamples (1.0.0)
   - CatalogUnitTests (1.0.0):
     - Resistor
@@ -22,7 +22,7 @@ EXTERNAL SOURCES:
     :path: components/Resistor
 
 SPEC CHECKSUMS:
-  CatalogByConvention: 5df5831e48b8083b18570dcb804f20fd1c90694f
+  CatalogByConvention: 1df2d770271921f668a99245c7c4c129e78941ee
   CatalogExamples: cafe3e4eae3abc948d96beb626657455c1dfb327
   CatalogUnitTests: b7a746f12abb31a905654521ee926ea007ab7275
   Resistor: 36a9ae98666be3b4f34d8133fad442fa87fdbce2

src/CBCCatalogExample.h

@@ -53,4 +53,7 @@
 /** Return a description of the example. */
 - (nonnull NSString *)catalogDescription;
 
+/** Return a link to related information or resources. */
+- (nonnull NSURL *)catalogRelatedInfo;
+
 @end

src/CBCNodeListViewController.m

@@ -85,6 +85,11 @@ - (NSString *)exampleDescription {
   return CBCDescriptionFromClass(_exampleClass);
 }
 
+- (NSURL *)exampleRelatedInfo {
+  NSAssert(_exampleClass != nil, @"This node has no associated example.");
+  return CBCRelatedInfoFromClass(_exampleClass);
+}
+
 - (BOOL)isPrimaryDemo {
   return CBCCatalogIsPrimaryDemoFromClass(_exampleClass);
 }

src/private/CBCRuntime.h

@@ -60,6 +60,9 @@ FOUNDATION_EXTERN UIViewController *CBCViewControllerFromClass(Class aClass);
 /** Create a description from the provided class. **/
 FOUNDATION_EXTERN NSString *CBCDescriptionFromClass(Class aClass);
 
+/** Create a link to related information from the provided class. **/
+FOUNDATION_EXTERN NSURL *CBCRelatedInfoFromClass(Class aClass);
+
 #pragma mark Fix View Debugging
 
 /**

src/private/CBCRuntime.m

@@ -138,6 +138,14 @@ BOOL CBCCatalogIsDebugLeaf(Class aClass) {
   return nil;
 }
 
+NSURL *CBCRelatedInfoFromClass(Class aClass) {
+  if ([aClass respondsToSelector:@selector(catalogRelatedInfo)]) {
+    NSURL *catalogRelatedInfo = [aClass catalogRelatedInfo];
+    return catalogRelatedInfo;
+  }
+  return nil;
+}
+
 #pragma mark Fix View Debugging
 
 void CBCFixViewDebuggingIfNeeded(void) {