poland (and includes a tiny refactor about corpus christi) refs #19
greece, first orthodox calendar, yay
Panama.
Merge pull request #61 from novapost/poland

poland
Merge pull request #63 from novapost/panama

Panama
Merge branch 'master' into greece

Conflicts:
	workalendar/core.py
	workalendar/tests/test_europe.py
Merge pull request #62 from novapost/greece

greece
Merge branch 'master' into finland

Conflicts:
	workalendar/europe.py
	workalendar/tests/test_europe.py