Openbr docs app

[JStehouwer]

No description provided.

[JStehouwer]

This adds docs(...) functionality to OpenBR transforms which are exposed via two endpoints.

Print out docs for a specific algorithm string:

$ br -algorithm "Read+Fork([Blur,Resize,Discard+Read])" -docs
Set algorithm to Read+Fork([Blur,Resize,Discard+Read])
Pipe(Transform transform): Project the output of each Transform into the next
    Read(Mode mode): Read the image from disk
    Fork(Transform[] transforms): Project the input template(s) through each transform and concatenate the results
        .BlurTransform->docs() not implemented
        .ResizeTransform->docs() not implemented
        Pipe(Transform transform): Project the output of each Transform into the next
            Discard(): Removes all matrices from a template.
            Read(Mode mode): Read the image from disk

Print out docs for all transforms (optional regex name matching):

$ br-docs --regex "Cvt"   
...
    .CvtTransform->docs() not implemented
    CvtFloat(): Convert the matrix to float32
    CvtUChar(): Convert the matrix to uint8

[JStehouwer]

TODO - Resolve issues when generating docs for transforms when the init() function fails when using default arguments.

[jklontz]

Got br -docs working again. How about this approach for handling initialization errors? I think you can remove _init()?

[jklontz]

I don't think we need a separate CLI app here. I think br -docs should do this when -algorithm isn't set.