fix table output for multibyte characters

Encoding unicode text with `str` does not work
for multibyte characters.
Update session to use single loader instance

Reduces memory bloat when running tests, which is causing
issues on some test systems.
Merge branch 'cache-loader' into develop

* cache-loader:
  Update session to use single loader instance
Merge branch 'quiver-support-unicode-row' into develop

* quiver-support-unicode-row:
  fix table output for multibyte characters
Add changelog entry for #721