Split Neo.Compiler.CSharp

[shargon]

Currently the compiler is Neo.Compiler.CSharp, however, it is an exe file, and we could distribute a nuget package that allows compiling without having to run the exe, as is done by referencing said project in the current unit tests.

Proposed solution:

• Create Neo.SmartContract.Compiler
• Export the package
• Use the /project package in Neo.Compiler.

[cschuchardt88]

You can use something similar to build-tasks

Ref: https://github.com/cschuchardt88/neo-express/blob/master/src/build-tasks/NeoCsc.cs

[shargon]

I think that it's better if we export the package and it's installed by dotnet tool install, then you can use the compiler easier