there are multiple executables

the dotnet is like git, so `dotnet compiler` just call `dotnet-compiler`

the first level tools ( dotnet-compile, dotnet-restore ) read the project json ( the only supported project file atm ) and pass argument to second level tools.

for example:

- dotnet compiler call dotnet-compile

- dotnet-compile read source files, references, defines from project.json and call dotnet-compile-csc with the source files as arguments.

- dotnet-compile-csc call csc

- if --native, another .net bytecode to native tools is called

and csc (csharp compiler) is bundled with the dotnet cli package.