filesystem: add COverrideFile and COverrideDirectory
filesystem: reduce code duplication in CBlurayFile, CMultiPathFile, CSpecialProtocolFile and CSpecialProtocolDirectory by deriving from COverrideFile/COverrideDirectory
[win32] update VS project files
[osx/ios/atv2] - sync xcode project
[android] re-enable gnutls in ffmpeg
[depends] bump gnutls to last stable version 3.3.10
[depends] fix nettle dylib target
[depends] fix gmp Makefile
cppcheck performance fixes in android/
cppcheck performance fixes in cores/dllloader/
addons: fix pluginsource.xsd
addons: remove unused "content" element from pluginsource.xsd
addons: remove "wingl" as a possible platform value from metadata.xsd
addons: fix repository.xsd
addons: add "cachepersistence" attribute to scraper.xsd
addons: add service.xsd
addons: add "res" element to skin.xsd
addons: remove unused "defaultthemename" attribute from skin.xsd
addons: rename "defaultresolutionwide" attribute to "defaultwideresolution" in skin.xsd
addons: "defaultresolution" attribute is optional in skin.xsd