When using config.h, it must be the very first include in all source
files since it contains #define that may change the compilation process
(eg libc structure layout changes when it's used to enable large file
support on 32 bit x86 archs). This commit adds it at the beginning
of all .c and .cpp files
uses VSC_Error with code==VSC_SUCCESS instead. This means that the VSC_Error
message is overloaded. Instead of the other option of adding a message id,
since the connection is TCP so no messages may be dropped or reordered, by
having each message followed by a response there is no ambiguity. Still
this commit adds a queue for messages that we only have one of which outstanding
at a time, i.e. send, wait for response, send the next, etc. This further
simplifies the logic, while not adding much overhead since only when spicec
starts up it has a situation where it needs to send two events (ReaderAdd
and ATR for Card Insert).
