Bf 312 improve select handling

initially i wanted to change only the handling of selects, but then i had to replace splinter with selenium in many files. which is good, because it's on the TODO list anyway.

so this pr covers:
* BF-312 use selenium selects
* BF-330 correct slowly type
* start to get rid  of splinter
* more test coverage
Use instead:
```
from salad.exceptions import (
    ElementDoesNotExist, ElementIsNotVisible, ElementAtIndexDoesNotExist)
```