fix imports from Core/Base not working

[disberd]

This PR fixes error within @frompackage when an import statement from Base or Core was used within the target package or directly from within the call to the @frompackage macro.

This closes #68

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (abce6d0) to head (6866da3).
⚠️ Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##            master       #71   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           12        12           
  Lines          783       786    +3     
=========================================
+ Hits           783       786    +3     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.