Support for new "-t" option (create new tab)

[jakubklos77]

With the new behavior of the terminal trying to match existing tab's path it is impossible to open a new tab with such existing path (working directory option -w).

• Suppose you have the terminal app open with the tab of location /tmp (running some command or simply waiting)
• Now you want to open another instance of the same path using:

io.elementary.terminal -w /tmp

This will simply activate the existing tab and nothing else will happen. Hence we cannot achieve the desired resuilt.

A new "-t" option to force a tab creation is the right solution (just lke we have for a new window).
This PR introduces the new option.

Newly, you can open the terminal with:

io.elementary.terminal -t -w /tmp

[jeremypw]

This does not add a new tab if there is no explicit working directory.
I think you need to change MainWindow.vala line 281 to

            if (directory == null || directory == "" || create_new_tab) {

[jakubklos77]

This does not add a new tab if there is no explicit working directory.
I think you need to change MainWindow.vala line 281 to

            if (directory == null || directory == "" || create_new_tab) {

You are right but the solutionn should be different. See my commit
00350b8. I think this is the right way

if (directory == null || directory == "") {
                if (notebook.tabs.first () == null || command != null || create_new_tab) { //Ensure at least one tab
                    new_tab ("", command);
                }

General conditon for empty directory remains but the new_tab conditon is extended for

• existing command - this way it will be executed as well
• create_new_tab

[jeremypw]

LGTM Thanks!