fix an indent bugs and add some new functions

[Undefeated-man]

1) make it available to identify which file the called function belongs to when our traceback depth is bigger than 1 -- automatically add the name of the file before printing the variables

2) adding "\n" before each "newish_string" and "Source path: xxx" to make the output nicer and easier to look

3) fixing an indent mistake at lines 363-364 in "tracer.py"

for example, this is my demo when depth=2:

[cool-RR]

Thanks anyway for trying to contribute.