[Pharo-project] OmniBrowser optimizations

Hi, Alex and me did some optimizations for the OmniBrowser framework. We focused on optimizing the updating of browser windows upon code changes (recompilation, recategorization, removing, doIts, etc.). Such browser updates are now an order of magnitude faster than before. For details, have a look at class OBBenchmarks in OB-Enhancements. To update you OmniBrowser installation, load the latest version of all installed OB-packages (typically OmniBrowser, OB-Standard, OB-Morphic, and OB-Enhancements) from http://source.wiresong.ca/ob. In Pharo, you can also execute 'ScriptLoader loadOBAlpha'. If you find any problems after this update, please let us know. Cheers, Alex and David