Fixed errors when scripts ran from other dirs

Java couldn’t compile or run the files due to not being able to find
them when the script was not run from the wargame directory. This new
line changes the directory to the one that the script is in before
compiling or running the files.
Merge pull request #1 from bman4789/master

Fixed errors when scripts ran from other dirs

For example, ./wargame-master/compile.sh would not work; it does with this patch.
Thanks Brian!