Add p => q, and s ? d1 : d0 to expression parsing
Add p => q, and s ? d1 : d0 to expression parsing

The '=>' operator is a symbolic Implies, and is right-associative
The ?: operator is a symbolic ITE, and is right-associative

cjdrake/pyeda,pombredanne/pyeda,pombredanne/pyeda,karissa/pyeda,pombredanne/pyeda,sschnug/pyeda,karissa/pyeda,karissa/pyeda,sschnug/pyeda,sschnug/pyeda,GtTmy/pyeda,cjdrake/pyeda,GtTmy/pyeda,cjdrake/pyeda,GtTmy/pyeda