looks like this:
```
let a=(condition ? s:var:'')
```
confuses older Vims and it complains about a missing colon. So make
parsing a bit easier and add a space in front of the second colon.
fixes#1629
commit ab49a1c7ae changed that no leading whitespace was added.
While this removed a double space in front of the current active
selected buffer, it removed one space too much for the non-current
buffers in the bufferline.
So partly reverse it and only add the space, if the highlighting groups
between each item did not change.
previously, when both tabs and buffers were displayed in the tabline, it
was not immediately obvious which side belongs to a buffer and which one
to a tab. Therefore, add [buffers]/[tabs] labels consistently.
Adding an option to prevent windows from being closed when a buffer in
the tabline is middle clicked and the clicked buffer is currently open
in a window.
When this option is enabled, instead of closing the window a new buffer
will be opened in all of the windows editing the clicked buffer instead.
This is my first pull request AND my first experience with vimscript, so
my apologies if this is a bit sloppy 😄
This is a new tabline extension, that displays both the buffers open and
the available tabs. This has been requested by #639 and fixes#639.
This is based on blings work on branch spike.
This uses the new highlight groups tab*_right, so that the separators
have the correct color. Also this makes some configuration variable
obsolete and therefore, they have been removed.
remove unused combined config variable, remove space after tab
