rebase to crm28
rebase fix
fix gtk crash on contextmenu

Fix #721
devtools jail feature
headless devtools and devtools-opened event
remove singleton lock on exit properly
mac fix
fix crm28 on windows
sync with upstream version 28.0.1500.11
bump to version 0.6.0-rc1
Support audio buffer size setting in manifest
setting dom storage quota from manifest
implement App.clearCache() for clearing the whole cache
Merge pull request #778 from greenheartgames/master

implement App.clearCache
bump mac version to 0.6.0
update for 0.6.0-rc1
remove macros which is not effective
rename dom-storage-quota to dom_storage_quota