errorlib: improve outline style of invenio.err

• Use standard outline marker '*' instead of '>'. Use '-' instead '*' to split locals by frame. (closes #581)
• Include more details about exception in the header (file, line and function where it occurred).
• Delete redundant text under 'Traceback details' and redundant line 'The following problem occurred on...'.
• Print all the frame stacks together at the same level.