fixed y-axis rendering bug

.settings/org.eclipse.jdt.core.prefs

dist/xchart-1.0.0.jar

src/com/xeiam/xcharts/AxisPair.java

src/com/xeiam/xcharts/AxisTick.java

src/com/xeiam/xcharts/AxisTickLabels.java

src/com/xeiam/xcharts/AxisTickMarks.java

src/com/xeiam/xcharts/PlotContent.java

src/com/xeiam/xcharts/PlotSurface.java

src/com/xeiam/xcharts/example/SwingChart4.java