Added methods for sending and receiving empty messages (OSC string + NIL). Altered arguments sent to signal callback functions, and updated test programs accordingly.
Altered testquery program to test empty query responses.
Changed declaration of signal handler to match current (experimental) usage
added functions for retrieving number of hidden inputs and device signals
Moved signal has_value property to mapper_db_signal data structure.
Reverted to passing signal value pointer in signal callback functions, and also added pointer to signal props since type and length are needed to parse value anyway. If the signal has no value, pass NULL. Receipt of empty signal message now sets has_value property to 0.
Fix unfinished sentence in tutorial.
Merge branch 'jni'
Changed second argument of msig_query_remote from void* to mapper_signal; added documentation for return value.
Merge branch 'null-signals'
Added check for null router return in handler_device_linkTo.
Only respond once to identical information requests in a given polling step (e.g. from multiple monitors on the network).
Moved paragraph on state queries and implicit mapping from known-limitations section to advantages-of-libmapper section.
Integrated device's update flag into bit flags.
Fixed bug when trying to calibrate with integer-typed source signal.
SWIG bindings: Add a required header for OS X.

Apparently not including arpa/inet.h leads to a segfault if
inet_ntoa() is called.  (Probably was passing bad data into it too,
since wrong data type was being passed as argument.)
SWIG bindings: use longs instead of ints to store opaque pointers.

Was crashing on 64-bit systems.
SWIG bindings: Perform Python's install step on "make install".
Add a libtool macro to check for the math library.
Explicitly link to the math library.