Add --odoo-load option

[guewen]

For testing some addons, we need to customize the --load option, should be added in

pytest-odoo/pytest_odoo.py

Lines 27 to 34 in 33e4e63

	def pytest_addoption(parser):
	parser.addoption("--odoo-database",
	action="store",
	help="Name of the Odoo database to test")
	parser.addoption("--odoo-log-level",
	action="store",
	default='critical',
	help="Log-level used by the Odoo process during tests")