corrected type conversion in parse_unary(), logical_op(), parse_bitwise_and(), parse_bitwise_xor(), parse_bitwise_or(). Added algorithm for TOK_TILDA.
_conv_to_int() added
added type conversion in Str_fromCharCode(), _charAt(), Str_indexOf(), Str_lastIndexOf(), Str_slice(), Str_substr()
_charAt() without argument corrected
String_ctor() corrected