Explicitly specify empty argument list as "void".
Make a small stylistic change.
Constify as many arguments as possible.
SConstruct: minor stylistic changes.
Make a small code simplification.
blockread: add an error check.
Move a declaration to the block it is used in.
Properly initialise struct fields.

Properly initialise the fields of the SF_BROADCAST_INFO struct to empty values
(0 and "").  This removes the need of the *terrible* workaround of copying the
fields to zero-initialised char* before storing them in the Matlab struct.
Increase constness of a variable.
Bump the copyright year.
Add a copyright line to each source file.