Geom data

Implement a way to specify `+ geom_something(data=df, aes(...))`. An example can be found in the tests:

```python
gg = ggplot(mtcars, aes("wt", "mpg")) + geom_point()
g2 = gg + geom_text(aes(label="name"), data=mtcars[mtcars.cyl == 6])
print(g2)
```

closes: https://github.com/yhat/ggplot/issues/116

Also included:
* add pycharm files/dir to .gitignore
* shorten the one long running test 
* fix some small syntax errors in the manual tests