simplify ExcInfo using linecache
move relevant FrameInfo code into constructor
replace ExcInfo by cleaner setup
separate source and context in cachable properties
move _find_classname to Frame._name
add util.keyboard
rename exception.py to traceback.py
add traceback.format_exc
name changes
ren log.traceback to stack, show call trace by def
move keyboard from util to traceback
fix frame source for decorated functions
rename traceback.keyboard to traceback.breakpoint
move breakpoint from traceback module to util