Older version CMake find_dependency has a defeat that COMPONENTS
find will fail. Find single dependency separately to avoid this issue.
Log: fix find_dependency error
* remove redundant "dtkwidget" in include directory;
* improve cmake, modify some variable names, use file() to collect
source files for scalability;
* add full target_link_libraries support.
Log: add full target_link_libraries support
Influence: all projects who include headers directly by path