Comprehensive build-time error reporting system. In particular: if an error occurs, the build will try to continue to identify any other potential problems so that they can be flagged too. Syntax errors are captured and dealt with programmatically, rather than just being echoed to stderr by node. Stack traces are parsed to pull out file and line information, and a distinction is made between the 'user' and 'internal' portions of the stack. All of this is at build time only -- it has not been extended to (run-time) server or browser yet. Also, no source maps yet, though line numbers are computed correctly for units within the linker.