Updates `Config::tryExpandPath()` to return a vector of expanded path
matches instead of a single path wrapped in an optional, with an empty
vector indicating no matches.
`Config::resolveConfigIncludes()` iterates over all of these matches,
while other instances of path expansion (such as finding the base config
path) retain their existing behavior and only use the first match.
Previously, the only way to select all the module labels was with the
following kind of selector:
```css
.modules-left > widget > label,
.modules-center > widget > label,
.modules-right > widget > label {
/* ... */
}
```
(and a matching block for the `box` containers).
Now, this can be expressed as
```css
label.module, box.module {
/* ... */
}
```
This reverts commit 2d33c20231 and
reapplies various patches for memory leaks.
The reason for the revert was a bug for a maximum duration interval
which caused sleep_for() to cause unpredictable behavior.
Adding support for middle, backward, and forward mouse buttons click events, adds config keys : "on-click-middle", "on-click-forward" and "on-click-backward"
Adding the key "format-alt-click" to choose what mouse clicks toggles the alternative format, when present. Possible values (in config): "click-right", "click-left", "click-middle", "click-forward", "click-backward". Other values have the same effect than "click-left". Previous behaviour was to toggle it whenever any click was registered and any click that was not handled by "on-click-right" or "on-click-left" occurred
