Add `unicode_text` argument for fuzzy_time to top-level themes
Specify temp_format argument for weather segment in ascii theme
Replace all unicode defaults with defaults from ASCII theme

Closes #1034
Merge pull request #1038 from ZyX-I/ascii-defaults

Use non-unicode defaults in Python code
Fix non-unicode error messages

Ref #645
Merge branch 'non-unicode-errors' into develop