0.5.2

- Add gitlab-ci for thunarx-python
- Update configure.ac.in syntax
- Remove checks with unused result
- Remove check for unused sys/wait.h
- Fix missing-prototypes
- Fix g_list_find_custom usage
- make distcheck now works !
- Update gtk-doc for thunarx-python
- Fix compilation with python3.8
- fix compilation issues with gcc-10
- Scan extension directories only once