Log: Initial focus on last commit as option

When using the Working Tree window as primary environment, showing the current working tree state in the log again when using the "Log" button for a repo is not very helpful for two reasons:

1) This information is most likely the same that was present in the Working Tree window that opened the log

2) Selecting the last commit requires an extra step

3) SmartGit needs to assemble the list of changed / new files, although this information is most likely never needed coming from the working tree.

Therefore, it would be good to have an option to switch directly to the last commit. The working tree state still can be at the top of the list, but it should be possible that this is not the entry with default focus.