add docs for Methods and Solve methods

[tokuma09]

This pull request adds some documents for Methods and Solve methods in cdp.jl.

Later I will add docs for Types, contructors and Simulate methods.

Document style is based on QuantEcon.jl.

[oyamad]

Thanks! For the doc style, please follow Games.jl rather than QuantEcon.jl (refer in particular to QuantEcon/Games.jl#25).

[tokuma09]

I got it. Later on, I'm going to change doc style based on Ganes.jl.

[tokuma09]

I rewrite docs for ContinuousDPs.jl for all functions and structs. I think this style is based on Games.jl.

[oyamad]

@tokupooh Thanks!

• Please remove type declaration in the header; see https://github.com/QuantEcon/Games.jl/issues/25#issuecomment-331830850.
• Please limit each line with 80 characters or fewer.

[tokuma09]

@oyamad Sure. I'll fix them.

By the way, do we need same documents for different methods ?
For example, s_wise_max! allows several types of arguments, depending on the dimensions of the problem. However, an objective of all methods is same.(I know this function works in different way internally.)

In this pull request, I add explanation for each methods, but Julia does not provide it for all methods.

Should I follow their doc style?

[oyamad]

Yes, please provide a docstring to each method. (We can elaborate later if necessary.)

[tokuma09]

I fix my docs for ContinuousDPs.jl by following the style where each line with 80 characters or fewer and type declaration.

In addition, explanation is consitent internally.

[tokuma09]

Thanks for comments. I correct them.