Latest Version of Vyper (0.1.0b6) Breaks Populus

[arjunaskykok]

• Populus Version: 2.2.0
• OS: linux

When using Vyper with version 0.1.0b6, the compilation process fails with this error:

bytecode = '0x' + compiler.compile_code(code).hex()
AttributeError: 'dict' object has no attribute 'hex'

This is the fix that I used for now:

-            bytecode = '0x' + compiler.compile(code).hex()
-            bytecode_runtime = '0x' + compiler.compile(code, bytecode_runtime=True).hex()
+            bytecode = compiler.compile_code(code)['bytecode']
+            bytecode_runtime = compiler.compile_code(code, ['bytecode_runtime'])['bytecode_runtime']

[jacqueswww]

@arjunaskykok The fix for this is here: #484