Grapher: Always reset colors at start of graphing

PBGitGrapher.m

@@ -17,6 +17,7 @@
 	refs = repo.refs;
 	repository = repo;
 	previousLanes = [NSMutableArray array];
+	[PBGitLane resetColors];
 
 	return self;
 }

PBGitLane.h

@@ -15,6 +15,8 @@
 - (id) initWithCommit: (NSString*) c;
 - (BOOL) isCommit: (NSString*) c;
 
++ (void) resetColors;
+
 @property(assign)  NSString* sha;
 @property(readonly) int index;
 

PBGitLane.m

@@ -14,6 +14,12 @@
 static int PBGITLANE_CURRENT_INDEX = 0;
 
 @synthesize sha, index;
+
++ (void) resetColors
+{
+	PBGITLANE_CURRENT_INDEX = 0;
+}
+
 - (id) initWithCommit: (NSString*) c
 {
 	index = PBGITLANE_CURRENT_INDEX++;