Slideouts are forced to connect to the next note

[NalihznehC]

Description
Slideouts are forced to connect to the next note, sometimes it will be ugly or unexpected.

To Reproduce

1. Open Powertab editor;
2. Press "ctrl"+"N" to create a new file;
3. Press "9" to create a note; Click on "Slide Out Of Downwards (X \ )" shown in the left Toolbox;
   Now it should look like this:
   
   which is what I wanted, neat and beautiful. However,
4. Press "→" twice and "↓" once to locate the position of the next note; Press "2" to create the second note;
   Now it will look like this:
   
   which is not what I wanted.

Additional Info
These forced connections are especially ugly when two notes are separated by a barline.
For example,

Version
Power Tab Editor 2.0 Beta (v2.0.0-alpha18-0-g1f2771b2)

[cameronwhite]

Confirmed, it should only do this for shift/legato slides between nodes, but not for a slide out of the note

[NalihznehC]

Now the lines are good, but the positions of "sl." are still remained unfixed.
I personally do not care about this label, but maybe someone will care about it in the future. Therefore, @cameronwhite if you have spare time, please also fix the "sl." labels. Thank you!

[NalihznehC]

Now the lines are good, but the positions of "sl." are still remained unfixed. I personally do not care about this label, but maybe someone will care about it in the future. Therefore, @cameronwhite if you have spare time, please also fix the "sl." labels. Thank you!

[cameronwhite]

Ah good catch, I somehow didn't notice that