In thread and frame format strings, it is now allowed to use Python functions...

In thread and frame format strings, it is now allowed to use Python functions to generate part or all of the output text
Specifically, the ${target ${process ${thread and ${frame specifiers have been extended to allow a subkeyword .script:<fctName> (e.g. ${frame.script:FooFunction})
The functions are prototyped as

def FooFunction(Object,unused)

where object is of the respective SB-type (SBTarget for target.script, ... and so on)

This has not been implemented for ${var because it would be akin to a Python summary which is already well-defined in LLDB

llvm-svn: 184500