auto-detect switch; support relative path

[vogler]

Is there something speaking against automatically selecting the opam switch by default?
Taking the result of opam switch show for the currently opened vscode workspace should be the right choice 99% of the time and if it's not, it's shown in the status bar and easy to change.

Another issue: I wanted to share my .vscode/settings.json but ocaml.sandbox.switch does not seem to support relative paths.

[mnxn]

Using opam switch show for toolchain selection can certainly be implemented.

I think that the sandbox configuration should be revisited to make it easier to share. That would include relative paths and possibly a separate file like how c_cpp_properties.json is used by the C/C++ extension .

[mnxn]

Regarding your second point, configuration files have been made a bit more portable with #424. The extension will now use workspace folder placeholder variables by default.