Wrap matlab test scripts with print information

These script are intended to be run as tests, but there is no visible
information whether scripts were actually executed.

Wrapping them up in print statements gives us confidence that scripts
were run from start to finish.

mex/test/segy.m

@@ -1,3 +1,4 @@
+disp('segy.m test suite: start');
 % test segyline
 
 % preconditions
@@ -279,3 +280,5 @@
 assert(abs(wr_line1(2,2,1) - 101.01001) < eps);
 assert(abs(wr_line1(3,2,1) - 101.01002) < eps);
 assert(abs(wr_line1(2,2,2) - 101.02001) < eps);
+
+disp('segy.m test suite: over');

mex/test/segyspec.m

@@ -1,3 +1,4 @@
+disp('segyspec.m test suite: start');
 % test segyspec
 
 % preconditions 
@@ -86,3 +87,5 @@
 for il = spec.inline_indexes'
     assert(il >= 1 && il <= 5);
 end
+
+disp('segyspec.m test suite: over');