Use libcurl 7.29.0.
Use libcurl 7.29.0 for prebuilt dylibs.
Merge branch 'master' into sam/async

Conflicts:
	CURLHandleSource/libcares.dylib
	CURLHandleSource/libcares.dylib.dSYM/Contents/Resources/DWARF/libcares.dylib
	CURLHandleSource/libcurl.dylib
	CURLHandleSource/libcurl.dylib.dSYM/Contents/Resources/DWARF/libcurl.dylib