pH-tabs: c_tab won't inherit from QWidget from now

They'll just contain the c_tab_header and c_tab_content
pH-tabs: c_tab subclasses won't call _f_init_layout
pH-tabs: Added useful methods in c_tab which is now just a container
pH-tabs: The c_tab_displayer now works differently
pH-tabs: Precised the tab that contains the c_tab_header c_tab_header
pH-tabs: Precised the tab that contains the c_tab_img
pH-tab: c_tab_calltree and c_tab_main modified to debug tabs
pH-tabs: Various changes to switch to another tab when one is closed
pH-tabs: Modified the calltree tab content
pH-tabs: Preparing to select the tab when clicked
pH-tabs: We can now select the tab we want
pH-tabs: Now things go back to normal