WebDAVFileSystem.cpp: Fix code style; Fix comments
WebDAVFileSystem.cpp: #define DEFAULT_HTTP_TIMEOUT 10
WebDAVFileSystem.cpp: neon_request_dispatch: uncomment check
Terminal.cpp: Add CheckForEsc
WinSCPFileSystem.cpp: Add TerminalCheckForEsc
WebDAVFileSystem.cpp: GetIsCancelled: Use CheckForEsc()
TWebDAVFileSystem::Open: Check if request is cancelled