Fixes:
1) Crashes in runner and file_utils
2) Binary strings being read in as payloads
Updates:
1) Clarified error messages in parser
2) Confusing variable names in test cases vs issues
Adds:
1) A `syntribos root` CLI sub command to display the current syntribos root dir
Change-Id: I22edf7a1f3d39724522aee88d08b00d299b67248