gopher2600: use fully qualified import path as module path

[mewmew]

Fixes #4.

This change was generated automatically by running:

$ find . -type f -name '*.go' | xargs -I '{}' sar -i '"gopher2600/' '"github.com/jetsetilly/gopher2600/' '{}'
$ find . -type f -name '*.go' | xargs -I '{}' goimports -w '{}'

Using goimports of x/tools to format imports and sar to search and replace (using regexp).

[JetSetIlly]

Merged. Thanks for the contribution. Smart solution too.