Add secondary CSS class based on the 'warning_level' field reported by UPower
over D-Bus. This makes it possible to add custom styling when the battery is
near empty.
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.
In file included from src/modules/upower/upower.cpp:1:
include/modules/upower/upower.hpp:25:16: error: no template named 'unordered_map' in namespace 'std'
typedef std::unordered_map<std::string, UpDevice *> Devices;
~~~~~^
In file included from src/modules/upower/upower_tooltip.cpp:1:
include/modules/upower/upower_tooltip.hpp:13:16: error: no template named 'unordered_map' in namespace 'std'
typedef std::unordered_map<std::string, UpDevice*> Devices;
~~~~~^