Update readme and improve variable names

Author: SamCarlberg

README.md

@@ -106,13 +106,14 @@ Then to make sure that OpenCV is installed prior to using any OpenCV code:
 
 ```java
 import edu.wpi.first.wpilib.opencv.installer.Installer;
+import edu.wpi.first.wpilib.opencv.installer.PlatformDetector;
 import org.opencv.core.Core;
 
 class Main {
 
   static {
     Installer.setOpenCvVersion(Core.VERSION);
-    Installer.installJni();
+    Installer.installJni(PlatformDetector.getPlatform().getDefaultJniInstallLocation());
     System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
   }
 

src/main/java/edu/wpi/first/wpilib/opencv/installer/Installer.java

@@ -113,28 +113,28 @@ public static void main(String[] args) throws ParseException {
         System.out.println("Installing specified OpenCV components");
         if (parsedArgs.hasOption("java") || parsedArgs.hasOption("all")) {
             try {
-                installJava(parsedArgs.getOptionValue("java", platform.getJavaInstallLocation()));
+                installJava(parsedArgs.getOptionValue("java", platform.getDefaultJavaInstallLocation()));
             } catch (IOException e) {
                 e.printStackTrace();
             }
         }
         if (parsedArgs.hasOption("jni") || parsedArgs.hasOption("all")) {
             try {
-                installJni(parsedArgs.getOptionValue("jni", platform.getJniInstallLocation()));
+                installJni(parsedArgs.getOptionValue("jni", platform.getDefaultJniInstallLocation()));
             } catch (IOException e) {
                 e.printStackTrace();
             }
         }
         if (parsedArgs.hasOption("headers") || parsedArgs.hasOption("all")) {
             try {
-                installHeaders(parsedArgs.getOptionValue("headers", platform.getHeadersInstallLocation()));
+                installHeaders(parsedArgs.getOptionValue("headers", platform.getDefaultHeadersInstallLocation()));
             } catch (IOException e) {
                 e.printStackTrace();
             }
         }
         if (parsedArgs.hasOption("natives") || parsedArgs.hasOption("all")) {
             try {
-                installNatives(parsedArgs.getOptionValue("natives", platform.getNativesInstallLocation()));
+                installNatives(parsedArgs.getOptionValue("natives", platform.getDefaultNativesInstallLocation()));
             } catch (IOException e) {
                 e.printStackTrace();
             }

src/main/java/edu/wpi/first/wpilib/opencv/installer/Platform.java

@@ -63,25 +63,25 @@ private static final class UserHomeHolder {
     }
 
     /**
-     * The location of installs for the Java library.
+     * The default location of installs for the Java library.
      */
-    private final String javaInstallLocation;
+    private final String defaultJavaInstallLocation;
 
     /**
-     * The location of installs for the JNI bindings. This should be in a location that is on {@code java.library.path}
-     * by default.
+     * The default location of installs for the JNI bindings. This should be in a location that is on
+     * {@code java.library.path} by default.
      */
-    private final String jniInstallLocation;
+    private final String defaultJniInstallLocation;
 
     /**
-     * The location of installs for the C++ header files.
+     * The default location of installs for the C++ header files.
      */
-    private final String headersInstallLocation;
+    private final String defaultHeadersInstallLocation;
 
     /**
-     * The location of installs for the native C++ libraries. This should be a default location on the path
+     * The default location of installs for the native C++ libraries. This should be a default location on the path
      * (e.g. {@code /usr/local/}).
      */
-    private final String nativesInstallLocation;
+    private final String defaultNativesInstallLocation;
 
 }