[stacktrace] pull file/line/name out of stack traces

[tstack]

The previous change just pulled out the entire stack trace from the log message. This change processes the stack traces to pull out the file/line/name
data.

Note: I haven't standardized an order for the call sites in a trace, Java goes one way and Python goes the other. Sigh...

Files:

• debugAdapter.ts: Add exceptionTrace field to LogMapping.
• lib.rs: The find_source_file_statements() can now match multiple source files since find_file() can now match multiple files. Add exception_trace to LogMapping and to_exception_trace() to StackTrace.
• main.rs: Change the meaning of --count to be the number of messages since we don't necessarily know how many lines are in a message.
• source_hier.rs: Since the Java stack trace code can only figure out the package and class name. The find_file() method has been changed to allow searching the tree for a partial path. For example, searching for "org/example/Main.java" will walk the entire tree looking for a match of that path. It will then return all possible matches of that path.