doc: Update more docstrings to have one sentence summary as first line. Reviewed io, java, linear-algebra, prefs, and set script directories. * scripts/io/beep.m, scripts/io/dlmwrite.m, scripts/io/importdata.m, scripts/io/strread.m, scripts/io/textread.m, scripts/java/javaArray.m, scripts/java/java_get.m, scripts/java/java_set.m, scripts/java/javaaddpath.m, scripts/java/javachk.m, scripts/java/javaclasspath.m, scripts/java/javamem.m, scripts/java/javarmpath.m, scripts/linear-algebra/bandwidth.m, scripts/linear-algebra/commutation_matrix.m, scripts/linear-algebra/cond.m, scripts/linear-algebra/condest.m, scripts/linear-algebra/cross.m, scripts/linear-algebra/duplication_matrix.m, scripts/linear-algebra/expm.m, scripts/linear-algebra/housh.m, scripts/linear-algebra/isdefinite.m, scripts/linear-algebra/ishermitian.m, scripts/linear-algebra/issymmetric.m, scripts/linear-algebra/istril.m, scripts/linear-algebra/istriu.m, scripts/linear-algebra/krylov.m, scripts/linear-algebra/logm.m, scripts/linear-algebra/normest.m, scripts/linear-algebra/null.m, scripts/linear-algebra/onenormest.m, scripts/linear-algebra/orth.m, scripts/linear-algebra/qzhess.m, scripts/linear-algebra/rank.m, scripts/linear-algebra/rref.m, scripts/linear-algebra/vech.m, scripts/path/matlabroot.m, scripts/prefs/addpref.m, scripts/prefs/getpref.m, scripts/prefs/ispref.m, scripts/prefs/rmpref.m, scripts/prefs/setpref.m, scripts/set/powerset.m, scripts/set/setdiff.m: Update more docstrings to have one sentence summary as first line.

--- a/scripts/linear-algebra/logm.m	Sun May 03 12:58:42 2015 -0700
+++ b/scripts/linear-algebra/logm.m	Sun May 03 15:36:23 2015 -0700
@@ -22,16 +22,19 @@
 ## @deftypefn  {Function File} {@var{s} =} logm (@var{A})
 ## @deftypefnx {Function File} {@var{s} =} logm (@var{A}, @var{opt_iters})
 ## @deftypefnx {Function File} {[@var{s}, @var{iters}] =} logm (@dots{})
-## Compute the matrix logarithm of the square matrix @var{A}.  The
-## implementation utilizes a Pad@'e approximant and the identity
+## Compute the matrix logarithm of the square matrix @var{A}.
+##
+## The implementation utilizes a Pad@'e approximant and the identity
 ##
 ## @example
 ## logm (@var{A}) = 2^k * logm (@var{A}^(1 / 2^k))
 ## @end example
 ##
-## The optional argument @var{opt_iters} is the maximum number of square roots
-## to compute and defaults to 100.  The optional output @var{iters} is the
-## number of square roots actually computed.
+## The optional input @var{opt_iters} is the maximum number of square roots
+## to compute and defaults to 100.
+##
+## The optional output @var{iters} is the number of square roots actually
+## computed.
 ## @seealso{expm, sqrtm}
 ## @end deftypefn