Issue #87 allow error bar color to match series color

xchart/src/main/java/com/xeiam/xchart/StyleManager.java

...xeiam/xchart/internal/chartpart/PlotContentLineChart.java

...in/java/com/xeiam/xchart/internal/style/GGPlot2Theme.java

...ain/java/com/xeiam/xchart/internal/style/MatlabTheme.java

.../src/main/java/com/xeiam/xchart/internal/style/Theme.java

...ain/java/com/xeiam/xchart/internal/style/XChartTheme.java