將 thisThursday() 系統函式改為 getThursday()/chkThursday()

淘汰 thisThursday() ,thisThursday_fb_format() ,nextThursday() ,prevThursday() ,isThursday() ,isFuture()
並用改良過的 getThursday(), chkThursday() 取代之
Merge remote-tracking branch 'github/develop' into devel

Conflicts:
	h4_invitation_notifier
	h4_invitation_notifier_facebook.py
	h4_invitation_notifier_ptt.py
	h4_wiki_notifier
	h4_wikidot_page_creater
將 thisThursday() 系列函式改為 getThursday()/chkThursday()