fix gcc warnings: format
fix gcc warnings: old-style-definition, strict-prototypes
fix gcc warnings: cast-qual in rfc6287.c
fix gcc warnings: sign-compare and maybe-uninitialized in rfc6287.c
remove dangling 'u' after PRIu64 macro
fix counter and Key input in orca_tool

ocra_tool.c :
- in init: improve key input validation (fail on all non-hexadecimal characters)
- in init: accept initial counter values from the whole
  counter range (64bit),  initial counter values can be given
  as hexadecimal numbers
- in info: print the correct counter value for counters > 0xffffffff

rfc6287.c, rfc6287.h:
- remove parse_num() from rfc6287 API
fix gcc warnings: cast-qual in ocra_tool.c and ocra.c

use memcpy to static buffer in macro to work around the fact,
that the dbopen(3) ``data base thang'' element 'data' is not
const
fix alignment when accessing int values from DB

the dbopen(3) access functions provide no guaranees about byte
string alignment: use memcpy to get integers
change ocra_tool command line interface

- init option -P <pinhash> added
- init option -c <counter> works with hex and decimal input
- help command removed
- info output format changed
update README.md