#167 pretty printer NPE if package and import on same line

[Alex Greif]

hi,
pretty printer throws a NullPointerException if the
package statement and one or more import statements
are on the same line like:
package p1.p2;import net.orthanc.flow4j.runtime.*;

beautify:
[pretty2]
formatting:C:\alex\project\test\prettyprint\untitled.java
[pretty2] java.lang.NullPointerException
[pretty2] at
org.acm.seguin.pretty.PrettyPrintVisitor.removeLastToken
(PrettyPrintVisitor.java:1184)
[pretty2] at
org.acm.seguin.pretty.PrettyPrintVisitor.visit
(PrettyPrintVisitor.java:979)
[pretty2] at
org.acm.seguin.pretty.PrettyPrintFile.apply
(PrettyPrintFile.java:129)
[pretty2] at
org.acm.seguin.pretty.PrettyPrintFile.apply
(PrettyPrintFile.java:105)
[pretty2] at org.acm.seguin.ant.Pretty.execute
(Pretty.java:161)
[pretty2] at
org.apache.tools.ant.UnknownElement.execute
(UnknownElement.java:269)
[pretty2] at org.apache.tools.ant.Task.perform
(Task.java:364)
[pretty2] at org.apache.tools.ant.Target.execute
(Target.java:301)
[pretty2] at
org.apache.tools.ant.Target.performTasks
(Target.java:328)
[pretty2] at
org.apache.tools.ant.Project.executeTarget
(Project.java:1215)
[pretty2] at
org.apache.tools.ant.Project.executeTargets
(Project.java:1063)
[pretty2] at org.apache.tools.ant.Main.runBuild
(Main.java:632)
[pretty2] at org.apache.tools.ant.Main.startAnt
(Main.java:183)
[pretty2] at
org.apache.tools.ant.launch.Launcher.run
(Launcher.java:197)
[pretty2] at
org.apache.tools.ant.launch.Launcher.main
(Launcher.java:56)