Create v56 branch.

Update to Chrome 56.0.2924.76 commit: https://bitbucket.org/chromiumembedded/cef/commits/d6b6d11ec412e897b4993705f69394030b93f7c2

Changes:

• Add ApplicationSettings.framework_dir_path
• Remove BrowserSettings.caret_browsing_enabled
• Mac: 10.9+ deployment target
• Mac: Allow configuration of framework path. Support crash reporting in unbundled apps. CEF Issue #1532.
• Fix OSR popup transparency. CEF issue #2099.
• Fix crash using WebRTC with TLS certs. CEF issue #2080.
• Fix localization of default context menu labels. CEF issue #2081.
• Windows: Support crash upload URLs with query component. CEF issue #1995.