v0.7.4rc1

• ef951e3 Merge pull request #153 from evo-company/rewrite-fragments-merge
• 2709a2d move validation step closer to parsing, make sure merge happens after validation
• 813bc1e simplify readers/graphql.py - collect fragments as is (no transformations)
• 60ef8da fix aliased fields in SplitQuery
• 50469ea rewrite fragments
• 593d052 update changelog for 0.7.3