Revert "Work around weird behavior in GCC 4.8 where it thinks this destructor's declaration and definition hase mismatching noexcept specs even though neither one has a noexcept spec at all."

This reverts commit c088dd95.

Reverted in favor of dwrensha's more complete fix.

Work around weird behavior in GCC 4.8 where it thinks this destructor's declaration and definition hase mismatching noexcept specs even though neither one has a noexcept spec at all.

Update Makefile.am to build new compiler.  Not bootstrapping yet, of course, since the C++ output plugin is not written.

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).

typos

Futex-based mutex and once-init implementations for Linux.  These are measurably faster -- and much smaller -- than the pthread-based implementations.

Allow SchemaLoader to use a callback to lazily load schema nodes, including dependencies of loaded nodes.

Implement mutex and once-init synchronization primitives.  Wrap pthreads for now, but plan on raw futexes later.

This should have been in the last commit but apparently I botched the --amend and then pushed without realizing.

Complete C++ .capnp parser.  Also, add a pretty-printing function for arbitrary Cap'n Proto objects which is like the existing stringification but uses whitespace (newlines an indentation) to make the structures more readable.