Move command line operations to Program

[PaoloOranges]

Not a bug fix or feature, a possible improvement.
I would like to separate the command line interaction from the downloader itself. In this way, GDAXDownloaderProgram.GDAXDownloader(tickers, resolution, fromDate, toDate) can be used in any other program not depending on user input or console in general.

Description

I moved input ARGS (tickers and resolution) checks to Program.cs: with tickers check on List.
I moved Console.ReadLine() to Program.cs so you can call GDAXDownloaderProgram.GDAXDownloader(tickers, resolution, fromDate, toDate) and it does not wait for the STD Input to return.

Related Issue

#12

Motivation and Context

It allows you to use GDAXDownloaderProgram.GDAXDownloader in any function/program with out depending on console IO

Requires Documentation Change

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• Refactor (non-breaking change which improves implementation)
• Performance (non-breaking change which improves performance. Please add associated performance test and results)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Non-functional change (xml comments/documentation/etc)

Checklist:

• My code follows the code style of this project.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.
• My branch follows the naming convention bug-<issue#>-<description> or feature-<issue#>-<description>