Update Parso and point to release Jedi

[MikhailArkhipov]

Continuation of #674

I think you left old files from a previous version of Jedi.
Jedi know depends on Parso, which is missing.
You default to the "preview" version
vscode-python/src/client/providers/jediProxy.ts

Lines 291 to 299 in 6015468

         if (typeof this.pythonSettings.jediPath !== 'string' || this.pythonSettings.jediPath.length === 0) { 
             if (Array.isArray(this.pythonSettings.devOptions) && 
                 this.pythonSettings.devOptions.some(item => item.toUpperCase().trim() === 'USERELEASEAUTOCOMP')) { 
                 // Use standard version of jedi. 
                 args.push('std'); 
             } else { 
                 // Use preview version of jedi. 
                 args.push('preview'); 
             } 

rather than the new version which was placed in "stable" (I think that's a hidden config setting...).
I can open a separate issue if you want.

[MikhailArkhipov]

5ccb9cd