Wrap up of Line Level History Browser

Hi,

Today is the last day of GSoC, here is a wrap up of the whole work of this summer from Line Level History Browser.

Generally, the goal of this project is to:
1. 'git log -L' to trace multiple ranges from multiple files;
2. move/copy detect when we reach the end of some lines(where lines
are added from scratch).

And now, we have supports in detail:
1. 'git log -L' can trace multiple ranges from multiple files;
2. we support the same syntax with 'git blame' '-L' options;
3. we integrate the 'git log -L' with '--graph' options with
parent-rewriting to make the history looks better and clear;
4. move/copy detect is in its half way. We get a nearly workable
version of it, and now it is in a phrase of refactor, so in the scope
of GSoC, move/copy detect only partly complete.

Now, the first series of patches of core 'git log -L' functionality is cooked in 'pu' and the move/code detect code is in a refactor. That's the general status of my project.

In the following days, some more work will be put into the refactor and I hope I can make the re-written version appear in next week. :)

Finally, many thanks to my mentor Thomas, he helped me on designing how to implement things and was very patient to point out the flaw of various version of 'git log -L' and this make me improve my code continuously. And thanks to Jens, Junio to provide so many valuable comments. Thanks a lot!