Fix obscure bug where allocating an empty struct causes trouble.  For reasons I don't yet fully understand, this actually caused a crash on 32-bit OSX builds (but not 64-bit, nor 32-bit Linux).

Rename non-group again, now to 'slot', which is much nicer.  Also introduce fixed lists as a third kind of field (but not implemented yet).

New method isFoo() exists for union fields only and returns true if foo is the active union field.

Switch to the new compiler.  All tests pass\!  Need to submit bootstrap copies of the generated code used by the compiler itself.  These bootstrap copies are still built by the old compiler at the moment.

Arrange for compiler to send to the code generator the complete contents of all files listed on the command line, all first-level dependencies of those files, and parent scopes of those dependencies, but nothing more.  This means it's sometimes possible to compile a schema file without parsing all transitive dependencies.  Also, in 'decode' mode, don't compile annotations, so that the files defining those annotations need not be opened at all.

Refactor compiler binary into a multi-tool with sub-commands like 'compile' and 'decode'.  The latter dynamically decodes binary input to text based on a provided schema file.

Fix compiler bugs.  Now test.capnp compiles to an identical schema to the old Haskell compiler, minus intentional changes.

Compiler actually running plugins!  Hooked it up to capnpc-capnp (the loopback plugin).  Working on getting the output identical to the old capnpc...  still a few bugs left.

Add utility code for really nice command-line option parsing and start using it in the compiler (still WIP).