[Kst] Generate vector bug

[Ben Lewis]

Hi Peter,

I've got another bug for you. Here are the steps to reproduce it.

1. Load the 9GB file. This step is necessary because it sets a large file as default. Using a large 
file makes the bug obvious.
2. Close Kst.
3. Start Kst with a new blank session.
4. Generate a new vector (Create > Vector > Generate). Note the 9GB file should be shown greyed out 
in the section below "Read from Data Source"
5. Click OK. Kst reads the 9GB file before it creates the new vector. Generating a new vector should 
not trigger a read of the previously opened file. On the 32-bit version Kst crashes because it can't 
read the 9GB file.

Would you like me to create a new bug report?

Ben