Small update after a long time.
Added an option file, located under "(YOUR DOCUMENTS FOLDER)\My Games\Sid Meier's Civilization 5\MODS\Unit Path Viewer (v 10)", in which you can change the colors of highlighted hexes. The file is named "UnitPath_Options.lua" and you can open it with any text editor, I suggest you use Notepad++[notepad-plus-plus.org].
Instructions are inside the file.

Added support for Multiplayer and Hot Seat. *** NOT TESTED ***
Jaii der Herr: changed how End Turn blocking types are handled making the MOD compatible with any game version (Vanilla, G&K, BNW, future...)

Added MOD instructions into the notification at game start.
Fixed a bug introduced in v. 7 for ''Route to'' workers that caused the INSTANT deletion of their stored path.
Better CTRL + SHIFT experience.
Changed highlight styles and a bit the colors.
Major code improvements.

Added a notification at game start to inform you that the mod is initialized.
Added an hotkey to show all units' destinations at once.
Added E.T.A. when clicking on the flag of units.
Bugfix regarding ''Route to'' workers that caused the premature deletion of their stored path.

Forgot to remove some garbage from the package

Added some in game notifications when the redirecting system is called.
Added a custom hex highlighting for workers with a "Route to" mission.
Added the highlight in red for the destination plot of automated workers.
Minor code changes.

Minor bug fix where if you give to a worker the command "Route to" while moving the stored path won't be deleted until completing the route.

Optimized the redirecting system, so now it is invoked only after pressing the "Next Turn" button.
Modified the counter to keep the path for two turns instead of one.
Minor code changes.

Major code changes, rewrote the script from the ground up.
If a unit's move will complete into the same turn, no path is stored or shown.
Added a counter to retain the path for one turn after that a unit reaches its destination or is given a new order.
If the destination plot is occupied by another unit, a new destination is chosen from the path. When selecting the redirected unit you'll see the same path as usual but in white the discarded hexes. If your unit is near enough to see the destination plot, no action is taken.

Implemented into the mod Pazyryk's work, so after loading a game all unit paths are kept.
Added an arrow that will show you the destination plot of automated workers.
Some code improvements.