savematfile() does not support boolean/logical variables with version>4

Reported by Samuel GOUGEON (@sgougeon)

BUG DESCRIPTION:
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Saving a boolean variable or matrix or hypermatrix with savematfile() yields an error:


ERROR LOG:
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-->savematfile("booleans.mat","-v7.3","ba","bv","bm")
Do not known how to get variable of type 4
 !--error 10000 
savematfile: could not save variable named ba.
at line     330 of function savematfile called by :  
savematfile("booleans.mat","-v7.3","ba","bv","bm")


HOW TO REPRODUCE THE BUG:
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ba = %t;
bv = rand(1,5)<0.5;
bm = rand(2,3)<0.5;
savematfile("booleans.mat","-v7.3","ba","bv","bm")


OTHER INFORMATION:
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Same thing with Scilab 6.0.1.
Same restriction with loadmatfile(), reported as bug 15567