fix synchronous xhr in webworkers by reintroducing code deleted in be163123
add chunked lazy sync XHR loading in Web Workers
Don't explode in emconfigure if no args are passed
Add `library_jansson` for JSON parsing.

Jansson is a C library for encoding, decoding and manipulating JSON data [1]. `library_jansson` mimics this interface (currently only for decoding) to perform JSON parsing in Javascript.

[1] https://github.com/akheron/jansson
Merge pull request #636 from larsxschneider/json_parser

Add `library_jansson` for JSON parsing.
mark jansson test as only for ta2
Merge pull request #638 from xrmx/emptyargs

Don't explode in emconfigure if no args are passed
improve node autodetection
disable jansson in SAFE_HEAP
disable test_gethostbyname without t2
Support for servers without byte serving, various small fixes
allow changing java heap size for closure via JAVA_HEAP_SIZE env var
stop working around v8 bug 1985 which was fixed a while ago
remove unneeded node checks
split up very large js files when passing them into js-optimizer and eliminator, to allow optimizing very large files without node hitting out-of-memory
UNALIGNED_MEMORY option to emulate unaligned reads/writes all the time, to support some nonportable code
support for SDL resize event
fix closure error in file packager
intel/linux webgl output test runner additions
support ALL.test in test runner