RangeFinder: set RNGFND_DIST_MAX parameter defaults based on driver

We can make the configuration of range finders a little easier for the users by setting the default RNGFND_MAX_CM and RNGFND_MIN_CM values to appropriate values based on the range finder driver.

So for example, the [teraranger one wiki page](http://ardupilot.org/copter/docs/common-teraranger-one-rangefinder.html) states:
- RNGFND_MAX_CM = 1400
- RNGFND_MIN_CM = 20

So we could probably add a couple of lines like this into the AP_RangeFinder_TeraRangerI2C::init() method:

- state.min_distance_cm.set_default(20)
- state.max_distance_cm.set_default(1400)

Start with AP_RangeFinder_TeraRangerI2C::init() and compare the documented TeraRanger One values in its wiki page. Check how driver state min_distance_cm and max_distance_cm defaults are set, then verify that each applicable driver uses appropriate documented defaults when configuration is created.

Written by the indexing model from the issue text.