All the paste formats are auto indented (used to be implemented only for the Python format)

[nekhvoya]

Now no matter which format is selected if a line starts with spaces the subsequent lines of the pasted text get auto indented.
This used to be the case only for the Python format.

Steps to reproduce:

1. Open Pinnwand
2. Select any format except from Python
3. Type any text
4. Go to a new line, type any number of spaces
5. Go to a new line

Actual result: the line gets auto indented.

Expected result: The line should not get auto indented (unless the selected format is Python)

Probably, the issue got introduced with this changes: #277

@supakeen , could you please take a look?