Add has_feature_version helper

[radarhere]

Adds has_feature_version() to Tests/helper.py.

This reduces some duplicate code, but also - at the moment, test_imagefontctl.py just catches a version exception

Pillow/Tests/test_imagefontctl.py

Lines 107 to 111 in 9f5d1f7

	try:
	draw.text((0, 0), "English あい", font=ttf, fill=500, direction="ttb")
	except ValueError as ex:
	if str(ex) == "libraqm 0.7 or greater required for 'ttb' direction":
	pytest.skip("libraqm 0.7 or greater not available")

It is theoretically possible that our C code is throwing the exception when it shouldn't, so it is better to check the version in Python first.