Fix 10.7 crash (Issue #1157).
According to https://developer.apple.com/library/mac/documentation/GraphicsAnimation/Conceptual/HighResolutionOSX/APIs/APIs.html#//apple_ref/doc/uid/TP40012302-CH5-SW20 -[NSImage setMatchesOnlyOnBestFittingAxis:]  was introduced in 10.7.4 not 10.7 as the NSImage class reference suggests.