Module for parsing stack traces and using them to guide Infer analysis

`type frame````=` `{`

`class_str : string;`
`method_str : string;`
`file_str : string;`
`line_num : int option;`

`}```
`type t````=` `{`

`exception_name : string;`
`frames : frame list;`

`}```
`val make : string ‑> frame list ‑> t`
`val make_frame : string ‑> string ‑> string ‑> int option ‑> frame`
`val frame_matches_location : frame ‑> InferBase.Location.t ‑> bool`
`val of_string : string ‑> t`
`val of_json_file : string ‑> t`