Color Switch (ColSw) is a program for CC:Tweaked for quickly editing your current palette.

Gist can be found here

Usage:

colsw apply [PATH]; applies the palette from the file and quits.
colsw [PATH]; opens existing palette file (or creates a new one)
colsw --help; prints out a helpful message.

ColSw uses a very simple file structure where a palette can be stored like this:

r, g, b
r, g, b
r, g, b
r, g, b
...

(Although technically this one is also valid):

r g b
r g b
r g b
r g b
...

(And I guess this one too?? It ain't strict, alright?):

|r|g|b|
|r|g|b|
|r|g|b|
|r|g|b|
...

Basically it just requires 16 lines of 3 integers ranging from 0 to 255.