Minor updates to api (changed float to CGFloat)

For the sake of completeness and portability changed an interface
declaration to be CGFloat instead of float.

PSTreeGraphView/PSBaseSubtreeView.m

@@ -23,11 +23,13 @@
 
 #define CENTER_COLLAPSED_SUBTREE_ROOT   1
 
-static UIColor *subtreeBorderColor(void) {
+static UIColor *subtreeBorderColor(void) 
+{
     return [[UIColor colorWithRed:0.0 green:0.5 blue:0.0 alpha:1.0] retain];
 }
 
-static CGFloat subtreeBorderWidth(void) {
+static CGFloat subtreeBorderWidth(void) 
+{
     return 2.0;
 }
 
@@ -41,7 +43,7 @@ @implementation PSBaseSubtreeView
 @synthesize nodeView;
 
 
-- (BOOL)isLeaf 
+- (BOOL) isLeaf 
 {
     return [[[self modelNode] childModelNodes] count] == 0;
 }

PSTreeGraphView/PSBaseTreeGraphView.h

@@ -203,7 +203,7 @@ typedef NSInteger PSTreeGraphOrientationStyle;
 
 // The style for tree graph orientation  (See the TreeGraphOrientationStyle enumeration above.)
 
-@property (nonatomic) PSTreeGraphOrientationStyle treeGraphOrientation;
+@property (nonatomic, assign) PSTreeGraphOrientationStyle treeGraphOrientation;
 
 //Returns YES if the tree needs relayout.
 
@@ -295,7 +295,7 @@ typedef NSInteger PSTreeGraphOrientationStyle;
 
 // The style for node connecting lines.  (See the PSTreeGraphConnectingLineStyle enumeration above.)
 
-@property (nonatomic) PSTreeGraphConnectingLineStyle connectingLineStyle;
+@property (nonatomic, assign) PSTreeGraphConnectingLineStyle connectingLineStyle;
 
 // Defaults to NO.  If YES, a stroked outline is shown around each of the TreeGraph's 
 // SubtreeViews.  This can be helpful for visualizing the TreeGraph's structure and layout.