[antlr] Support negative number

[at15]

We need negative number, but if we put the sign into the token INT and DOUBLE, it would create trouble for 1 - 2, it is no longer INT MINUS INT, but INT INT.

// what we want
irk> -1
-1 : float
irk > 1 - 2
-1 : float

• https://github.com/antlr/grammars-v4/issues/212

• http://www.antlr3.org/pipermail/antlr-interest/2006-August/017440.html

  Don't bother trying to handle them in the lexer, handle uniary-minus in the parser instead

• https://liucs.net/cs664s16/antlr.html

• http://teaching.idallen.com/cst8152/97s/unary_minus.html

• [x] add unary operations

[at15]

oops, just tried it again 1 + 2 - 3 is broken .... line 1:3 missing ';' at '-'