Increase TSTool memory

[smalers]

I tried processing a range of dates as usual in order to complete running the historical data. However, TSTool exited with an out of memory error. To fix this, the code needs to be updated to increase the -Xmx option. Since the operating system and Java are 64-bit, there should not be an issue to increase. Don't want to run into this again operationally, especially for a few years, so I recommend increasing the memory to 1536m and see how that goes. I could have made this change myself, but I want Josh to make sure it is updated in the right place and is committed to the repository.