cli: Add version name from programs Cargo.toml to IDL

[tomlinton]

This required some changes to the manifest discovery code because anchor idl parse doesn't necessarily execute from within the program directory like the anchor build does.

It might be cleaner to do this all in lang/syn/src/idl/file.rs but it probably requires duplicating that manifest discovery code rather than just passing the version as an arg.

Closes #349

Example:

anchor idl parse --file programs/basic-0/src/lib.rs
{
  "version": "0.1.0",
  "name": "basic_0",
  "instructions": [
    {
      "name": "initialize",
      "accounts": [],
      "args": []
    }
  ]
}

[fanatid]

Any chance to add a test for this feature? Or we do not need it?

[tomlinton]

Sure, happy to add a test!