Tutorials
added tutorials, let me know if you guys would like the output in a different format.

@jorisvandenbossche look ok to you?
 Just made two really small comments, for the rest loooking OK!

@david Can you also squash the commits (https://github.com/pydata/pandas/wiki/Using-Git)? Then it is OK to go in.
 This section of the docs will probably grow to include dozens of links,
it doens't make sense to include such ToC detail for each of them. I think
a link and a blurb would pan out better.
 I am ok with the 2 existing tutorials., they are easier to navigate and sub-menus. Let's see how it goes (when the docs build on the dev site) :)
 Sorry for the delay guys, I'm pretty clueless about github. How do I squash???

git fetch upstream
git rebase --interactive upstream/master
make changes and then push them back to github??
 https://github.com/pydata/pandas/wiki/Using-Git

pretty close....just 's' the ones you want to squash
push with `-f` to force it to overwrite
 git remote add upstream git://github.com/pydata/pandas
git fetch upstream
git rebase --interactive upstream/master

then got this msg and I am stuck?
![image](https://f.cloud.github.com/assets/2744117/1944299/34503308-7fb8-11e3-8eeb-5be0cf467485.png)
 change the 'pick' to 's' for all but the first will make them all into 1 commit effecitively

save

force push
 @pichonz In normal mode do `ggjV3j` then in command mode do `:'<,'>s/pick/squash/g`.
 Let me know if I messed something up, this process is pretty painful.
 Just takes a bit of getting used to. git can be frustrating at first. Looks like you have an empty merge there.

do

``` sh
git reset --hard HEAD~1
git push --force
```
 @pichonz If you are not used to vim, you can also configure git to use eg notepad++ for the interactive rebasing (then it is easier to change the 'pick' in 'squash'). See eg here: http://stackoverflow.com/questions/1634161/how-do-i-use-notepad-or-other-with-msysgit
 @pichonz , I squashed and pushed to master.  thanks for the contribution. e44d52d
