v1.4.0

Release v1.4.0

Release v1.4.0 is improvement release.
New features include:

 - support for "remainder" options/arguments which
   works similarly as it does with getopt. Optionally,
   you can use option "--" to stop parsing and put
   rest of command-line options to remainder.
   Remainder is available for user via remainder() function
   of usage_t class.
 - Options and arguments are now parsed once during construction
   of usage_t.
 - separator = is now supported, for example in example program,
   you can use `--age 10` or `--age=10` to archieve same result.
 - arguments for option can now be set to either not used, required
   or optional.
 - minimal argument validation is now supported for following types:
   bool, integer, float, string, hex
 - info structure has now even more detail.
 - default function for reporting parsing errors, is now present

Signed-off-by: Oskari Rauta <oskari.rauta@gmail.com>