no invokeFun callback when invoked function throws an exception

[msridhar]

It seems that analyses do not receive the invokeFun callback when the invoked function throws an exception. So, if you definitely want some analysis action to be run for a function call, you need to do it in invokeFunPre. At the least, we should document this. At some point, we may want to think about a new analysis interface that puts more of the exception handling burden on analyses, in return for greater flexibility and better performance.