Log improvement

[andxu]

1. jdi event
   2.vscode request/timestamp when uncaught error happens.

[Eskibear]

JDI events

0. Do we really need to log the exact sequence of all the events? (That would be large for long debug sessions).
1. Or we just log the count of each kind of events. (But most of them are actually redundant with command count information, command count seems enough for diagnosis)

So whether to log it? in what form?

[Eskibear]

common JDI events log added in #65