hex_dump_string function for debug output

will be used to dump UTF-8 and binary strings, showing non-ascii and control characters. UTF-8 represented as binary string (with special UTF-8 indicator appended to string). should also work with broken UTF-8
improve hex_dump_string

escape some control characters as perl escapes (tab, cr, lf) + quote entrie string + escape quotes and backslash
hex_dump_string - bug in test fixed
Begin of Warnings/Errors/Fatals rework

1) 'confess' now produces "UNEXPECTED ERROR" with a stacktrace and return code 1
2) 'die(exception(message))' now produces 'Fatal error' message and return code 1
3) "FATAL ERROR" has a suffix: empty string, parent (i.e. after fork()) and 'child'
4) Errors will now terminate children with SIGUSR2
5) Some code added to Utils to process errors and messgaes
6) SIG{DIE} removed, errors catch done now using eval{}
7) there are several error catch blocks - default, after fork and in children
8) one typo fixed in variable name
9) 'OK DONE' now always (i.e. for all commands) printed in case of success
rework and unit test for invalid characters in filename exception
comment added
Invalid UTF-8 chars in filename message improved
Some more work for invalid character in filename exception handling

1) Check for TAB,CR,LF in filename before everything else, as some perl modules throw additional errors/warnings in case LF in filename
2) Only TAB,CR,LF produce sane error message, other glitches (via _can_read_filename_for_mode) produces "confess" stacktrace
3) slow sanity_relative_filename performed only after _can_read_filename_for_mode
4) test fixes, it should use correct filenames inside transfer root
5) tests added for TAB,CR,LF in filenames
Merged master
Merge branch 'master' into development

Conflicts:
	lib/App/MtAws/Utils.pm
Move code related to IPC protocol to one file: LineProtocol.pm
Some unit tests for LineProtocol
small fix in test - use tmp file with desired name
README - fix obsolete link
Line Protocol - write/read JSON data with separate sysread/syswrite statement to avoid string concatenation and encoding issues in the future
small helper for exception handling pattern
Exceptions - more tests
Exceptions improvements/integration

1) dump_error moved to Exceptions.pm
2) exception_message implemented
3) Exceptions.pm integrated to main program
4) Utils.pm cleaned from old code
5) Exception tests improved
6) Existing tests fixed
TODO added
Exceptions - improve Journal exceptions with new Exceptions API