Allow spaces in IDE install path on Linux

The startup bash script lacked quotes in some places, causing it to
interpret part of the path to the splash image as the main class and
fail to start:

arduino: line 29: [: /home/a/Arduino: binary operator expected
Error: Could not find or load main class IDE.lib.splash.png

For the -splash option, simply adding quotes was not sufficient. If no
splash screen was to be used (so when $SPLASH was empty), using
"$SPLASH" would result in an empty argument being passed to java, which
was then interpreted by java as the name of the base class.

To allow spaces to occur in the -splash option, but also allow it to be
omitted entirely, options to java are now passed through the
$JAVA_OPTIONS array. By using the special "${JAVA_OPTIONS[@]}" syntax,
each element in the array is expanded into a single argument, even when
spaces are present inside (this is identical to what happens with "$@").

This fixes #3950

Author: matthijskooijman

build/linux/dist/arduino

@@ -3,9 +3,9 @@
 APPDIR="$(dirname -- "$(readlink -f -- "${0}")" )"
 
 for LIB in \
-    $APPDIR/java/lib/rt.jar \
-    $APPDIR/java/lib/tools.jar \
-    $APPDIR/lib/*.jar \
+    "$APPDIR"/java/lib/rt.jar \
+    "$APPDIR"/java/lib/tools.jar \
+    "$APPDIR"/lib/*.jar \
     ;
 do
     CLASSPATH="${CLASSPATH}:${LIB}"
@@ -17,18 +17,19 @@ export LD_LIBRARY_PATH
 
 export PATH="${APPDIR}/java/bin:${PATH}"
 
-if [[ "$@" == *"--upload"* || "$@" == *"--verify"* || "$@" == *"--get-pref"* || "$@" == *"--install-board"* || "$@" == *"--install-library"* ]] ; then
-	SPLASH=""
-else
-	SPLASH="-splash:$APPDIR/lib/splash.png"
-fi
-
 export JAVA_TOOL_OPTIONS=`echo $JAVA_TOOL_OPTIONS | sed 's|-javaagent:/usr/share/java/jayatanaag.jar||g'`
 
 JAVA=java
-if [ -x $APPDIR/java/bin/java ]; then
+if [ -x "$APPDIR/java/bin/java" ]; then
   JAVA=$APPDIR/java/bin/java
 fi
 
-$JAVA -DAPP_DIR="$APPDIR" -Dswing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel $SPLASH processing.app.Base "$@"
+# Collect options to java in an array, to properly handle whitespace in options
+JAVA_OPTIONS=("-DAPP_DIR=$APPDIR" "-Dswing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel")
+
+if [[ "$@" != *"--upload"* && "$@" != *"--verify"* && "$@" != *"--get-pref"* && "$@" != *"--install-board"* && "$@" != *"--install-library"* ]] ; then
+	JAVA_OPTIONS+=("-splash:$APPDIR/lib/splash.png")
+fi
+
+$JAVA "${JAVA_OPTIONS[@]}" processing.app.Base "$@"