We used to use NSObjects, which was really expensive, because for each commit
as many as 100 graphlines can be created. By preallocating them and not
using NSObjects in general, we gain a massive speedup
This adds the "hasRef" boolean member in PBGitCellInfo which is set to true
if the specific commit has symbolic refs.
This is the first part in supporting labels just like gitk has. For now,
commits with refs are just displayed with a red circle.
Things that need to be done to support all refs:
* Make the NSDictionary in PBGitRepository contain arrays of refs,
not a single string
* Make PBGitGrapher store all refs of a commit in the PBGitCellInfo
* Figure out a nice way to display the labels in PBGitRevisionCell
This uses more Cocoa classes to draw the lines, making it easier to
understand and hopefully maintain.
Furthermore, we use less memory now, which is nice, but all the
dynamic arrays probably mean more CPU usage.
Nathan Kinsinger