2.5.0

• Do not overwrite the fish_colors file when updating the current prompt (#248).
• Remove fetched packages from ~/.config/fisherman when there is a fetch error (#247).
• Fixed a bug where undefined fish_color_* universal variables were set to incorrect values.
  • No longer generates a false color variable for undefined values; it will now be ignored (#246).
• Adopted package dependency reference counting (#226).
  • We can now remove packages installed as dependencies of other packages when the parent is removed.
  • Introduced a new universal variable, $fisher_dependency_count, to keep track of the names of installed packages.
• Improved self-uninstall by querying __fisher-* functions and erasing only matches instead of hardcoding variable names.