add an optional node to FS.ErrnoError, and use it in stat to tell if an error is about the relevant file - if not, it occurred when looking up its parents, and we should emit ENOTDIR; fixes #2669
force llvm debug info in SAFE_HEAP>=2 in slowcomp
do not save debug info if js opts will remove it anyhow
better warning when no java
save llvm debug info for source maps, even if js opts run
fix testcase 1 of #1714, proper handling of resumeException, and remove hack in __cxa_begin_catch
ensure emscripten heap is at least 64K
fix asm.js validation for coroutine
Merge pull request #2673 from coolwanglu/coroutine_asm_fix

fix asm.js validation for coroutine
Merge pull request #2671 from hamishwillee/incoming

Fixes to the downloads section and building from source.
Finished draft framework for bind.h