add support for nullable/optional properties

[richorama]

A c# property like this:

public int? Foo { get; set; }

should emit this typescript

Foo?: number;

[coveralls]

Pull Request Test Coverage Report for Build 4

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.04%) to 99.18%

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Files with Coverage Reduction	New Missed Lines	%
/src/CsToTs/TypeScript/Helper.cs	2	98.73%

Totals
Change from base Build 11:	0.04%
Covered Lines:	242
Relevant Lines:	244

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💛 - Coveralls

[umutozel]

Thanks!
Published with 1.3.9 NuGet.

[richorama]

thank you!