API Changes: AssetPackTrace provide a Stream (previously a List)
An AssetPackTraceEventAccumulator can be used to keep events.
bug fix: AssetPackTraceEvent include error message into its label
API changes: AssetManager.loadAndRegister
* bug fix swap url and type parameters of AssetManager.loadAndRegister to match AssetManager.loadAndRegister
* AssetManager.loadAndRegister splitPoint between baseUrl and assetUrl move +1 (to support url without '/', and to include last '/' into baseUrl)
add ProgressControler to display asset loading progression via
 html5 progess.value or element.style.width.
Fix warning
80 columns fix
80 columns fix
Update to typed_data library.

Signed-off-by: John McCutchan <john@johnmccutchan.com>
Merge pull request #21 from davidB/exp_progressbar

Progress Bar
fix #22 : no longer read/write the entry "name" in .pack (remove duplication)
add test to check Uri behavior
use Uri to resolve urls (no longer need to define baseUrl and assetUrl)
update test (data, path, url) to reflect change in the url management (pack , imap, tmap)
optim: doesn't dump into json empty loadArguments and empty importArguments
adapt packgen to follow new layout (now it generate file into the directory : asset/_.pack)
+ refactor of packgen_tests (previous code fail to run test in sequences) so after lot of try, I change to 1 test that run the sequences of operations)
update packlist (to sdk and new layout of pack)
Merge pull request #25 from davidB/dev_packlayout

pack layout (and url resolution)