Extend totalSizeInWords() to also return a count of capabilities, which helps when a separate capability table needs to be allocated as well.  Use this in the RPC system.

Fix bug handling absolute source paths with no --src-prefix -- just output to the same directory in this case.

Define new KJ constants for min/max integer values and inf/nan, then remove all use of numeric_limits.

Extend 'capnp const' to support evaluating field default values as well as inner members of a value.

Make 'capnp decode' heuristically detect and warn when the wrong format flag (e.g. --packed, --flat) is used.

Pull TextBlob out of capnpc-capnp and into KJ as kj::StringTree.  Use it in the stringification code to make that code cleaner and avoid using iostreams.

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.