Check for octave in some version-specific tests

I have checked all these in Octave as I made the changes.

Author: cbm755

@chebfun/nextpow2.m

@@ -25,7 +25,7 @@
 
 % NEXTPOW2 is not vectorized in versions of MATLAB prior to R2010a.  Vectorize
 % it manually if we're running on older platforms.
-if ( verLessThan('matlab', '7.10') )
+if ( ~is_octave() && verLessThan('matlab', '7.10') )
     mynextpow2 = @nextpow2Vectorized;
 else
     mynextpow2 = @nextpow2;

tests/chebfun/test_airy.m

@@ -28,7 +28,7 @@
         for scale = 0
 
             % AIRY does not support the "scale" input prior to R2013a.
-            if ( compatible_verLessThan('matlab', '8.1') )
+            if ( ~is_octave() && verLessThan('matlab', '8.1') )
                 F = @(x) airy(K, (1+im*1i)*x);
             else
                 F = @(x) airy(K, (1+im*1i)*x, scale);

tests/chebfun/test_nextpow2.m

@@ -12,7 +12,7 @@
 
 % NEXTPOW2 is not vectorized in versions of MATLAB prior to R2010a.  Vectorize
 % it manually if we're running on older platforms.
-if ( verLessThan('matlab', '7.10') )
+if ( ~is_octave() && verLessThan('matlab', '7.10') )
     mynextpow2 = @nextpow2Vectorized;
 else
     mynextpow2 = @nextpow2;

tests/classicfun/test_minus.m

@@ -70,13 +70,13 @@
 g = bndfun(g_op, data, pref);
 try
     h = f - g; %#ok<NASGU>
-    if ( verLessThan('matlab', '9.1') )
+    if ( ~is_octave() && verLessThan('matlab', '9.1') )
         pass(18) = false;
     else
         pass(18) = true;
     end
 catch ME
-    if ( verLessThan('matlab', '9.1') )
+    if ( ~is_octave() && verLessThan('matlab', '9.1') )
         pass(18) = strcmp(ME.message, 'Matrix dimensions must agree.');
     else
         pass(18) = false;

tests/classicfun/test_plus.m

@@ -73,13 +73,13 @@
 g = bndfun(g_op, data, pref);
 try
     h = f + g; %#ok<NASGU>
-    if ( verLessThan('matlab', '9.1') )
+    if ( ~is_octave() && verLessThan('matlab', '9.1') )
         pass(18) = false;
     else
         pass(18) = true;
     end
 catch ME
-    if ( verLessThan('matlab', '9.1') )
+    if ( ~is_octave() && verLessThan('matlab', '9.1') )
         pass(18) = strcmp(ME.message, 'Matrix dimensions must agree.');
     else
         pass(18) = false;