Fix usage and flag processing.
 Reimplement toml_free as a walker.
make interface compatible with burntsushi tests when called as 'parser_test'
Pass burntsushi test 'array-mixed-types-arrays-and-ints'
Pass burntsushi test 'duplicate-keys'
Pass burntsushi test 'duplicate-tables'
Pass burntsushi test 'empty-implicit-table'
pass burntsushi test 'datetime'
pass burntsushi test 'bool'
pass burntsushi test 'string-bad-escape'
pass burntsushi test 'string-byte-escapes'
pass burntsushi test 'array-empty'
pass burntsushi test 'string-escapes'
pass burnsushi test 'key-two-equals'
Use 64 bits for int size
 pass burntsushi test "long-float"
 pass burntsushi test 'key-space'
pass burntsushi test 'arrays-hetergeneous'
pass burntsushi test 'key-hash'
pass burntsushi test 'float-no-trailing-digits'