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/java/javaclasspath.m	Sun May 03 12:58:42 2015 -0700
+++ b/scripts/java/javaclasspath.m	Sun May 03 15:36:23 2015 -0700
@@ -31,12 +31,12 @@
 ## @item If no output is requested, the dynamic and static classpaths are
 ## printed to the standard output.
 ##
-## @item If one output value @var{dpath} is requested, the result is
-## the dynamic classpath.
+## @item If one output value @var{dpath} is requested, the result is the
+## dynamic classpath.
 ##
-## @item If two output values@var{dpath} and @var{spath} are
-## requested, the first variable will contain the dynamic classpath and
-## the second will be contain the static classpath.
+## @item If two output values@var{dpath} and @var{spath} are requested, the
+## first variable will contain the dynamic classpath and the second will
+## contain the static classpath.
 ## @end itemize
 ##
 ## If called with a single input parameter @var{what}: