Pycapnp-async

- Fix problem with to_dict

- Add _DynamicStructBuilder.to_bytes() and <struct module>.from_bytes()
- Change == on StructSchema to return cbool
- Add Builder and Reader ABCs for each struct type

- Fix handling of empty path '' in load_module
- Add from_dict
- Fix bug in exception handling for which(). Also standardize exceptions.
- Change import hook to require modules to end in '_capnp'
- Add import monkey patch function.
- Change naming for functions to conform to PEP 8. Also deprecate old read/write API
- Update preferred method for reading/writing messages from files

- Forgot to change project name in setup.py

- Change all references to old project name (change from capnpc-python-cpp to pycapnp)
- Change DynamicValue.Reader lists to be returned as _DynamicListReader
- Unify setters for DynamicList and DynamicStruct
- Add shortcuts for reading from / writing to files. In Python, it doesn't make much sense to force people to muck around with MessageReaders and MessageBuilders since everything is landing on the heap anyway. Instead, let's make it easy: MyType.read[Packed]From(file) reads a file and returns a MyType reader. MyType.newMessage() returns a MyType builder representing the root of a new message. You can call this builder's write[Packed]To(file) method to write it to a file.
- Store Builders by value rather than allocate them separately on the heap (matches treatment of Readers). v0.3 fixes the bug that made this not work.
- Wrap MessageBuilder::setRoot().
- Add tests based on TestAllTypes from the C++ test.capnp. Fix problems uncovered in capnp.pyx.
- Implement __str__ and __repr__ for struct and list builders. __str__ uses prettyPrint while __repr__ shows the type name and the low-whitespace stringification. Also implement __repr__ for StructSchema, just because why not?

- Change load to use a global SchemaParser. Make structs settable as field
- Add docstrings for new functions and _DynamicResizableListBuilder