Terminal doesn't sanitize strings when reading/writing to dconf

[Raphael Isemann]

To reproduce:
Open terminal and close all tabs beside one.
Then:
$ cd
$ mkdir a,b a b # note: mkdir a,b with a comma between the letters
$ cd a,b

Close the terminal and reopen it

You have now two tabs in ~/a and ~/b instead of one tab in ~/a,b

Expected behavior:

One tab in ~/a,b

Relevant-code:
Line 533 in PantheonTerminalWindow.vala
tabs += t.get_shell_location () + ",";

Solution:

We shouldn't use a character for separating that is allowed in a path or do character-stuffing to escape relevant commas.