Wrong test data for Resource groups

[goganchic]

Recently I've found such test https://github.com/apiaryio/snowcrash/blob/master/test/test-ResourceGroupParser.cc#L103-L133

It tries to process such apib with resource group parser:

# Group
## /r1
p1
## /r2
p2

This data will not match resource group regexp which requires some name after "Group" keyword.

I think this test is wrong and should be modified or removed. It is not possible to have anonymous groups now.

[abtris]

Migrated to apiaryio/drafter#629