Documentation samples for binary classifiers

[sfilipi]

Similar to the sample code for SDCA regression, we need samples for the binary classifiers:
SDCA
AveragedPerceptron
FastTree
LightGBM

There are two things to do, to resolve this issue:

1. Add a sample for each of the trainers in Microsoft.ML.Samples/Trainers.cs
   The samples can look similar to the cookbook example
   Download the adult dataset for the data to use.
   Take a look at the SDCA example, for reference.

2. Add a link to the xml documentation of SDCA
   AveragedPerceptron
   FastTree
   LightGBM
   to reference the new sample methods, like the one in SDCA has.

[bojanmisic]

I'd like to work on this one, but wouldn't want to enter in a collision with someone. Is it possible to be assigned to this one?

[sfilipi]

Thanks @bojanmisic. It doesn't look like we can assign it, but claiming it on the comments might be good enough. Tag me if you have questions.

[wschin]

Maybe add a new label "assigned"? @shauheen, any comment?

[justinormont]

Well, once someone claims it, we can simply remove the help wanted and up-for-grabs tags.

[bojanmisic]

@sfilipi, thanks! I believe the link to the cookbook examples has shifted, since the file has been changed recently. Would you like me to use static or dynamic API?

[sfilipi]

Dynamic is fine; I was going to log another bug for the static examples, after arranging the structure of that project.
Thanks for picking this up.

[sfilipi]

@bojanmisic checking: are you still planning to work on this?

[bojanmisic]

@sfilipi, yes! I plan to work on that during the weekend. I have a strong will to contribute, just been crushed with work last two weeks. Sorry for the inconvenience, if you think someone can get it earlier, feel free to reassign.

[sfilipi]

@bojanmisic just checking, before putting the Assigned label and removing the other labels. It is yours, take your time. Take a look at PR #136. I am adding a dateset for binary trainers there.Feel free to adopt if it doesn't get merged soon.