Read most protocol params from common/params.json

* Add params package with exported variables generated from
  github.com/ethereum/common/blob/master/params.json
* Use params package variables in applicable places
* Add check for minimum gas limit in validation of block's gas limit
* Remove common/params.json from go-ethereum to avoid
  outdated version of it

core/vm/stack.go

@@ -5,8 +5,6 @@ import (
 	"math/big"
 )
 
-const maxStack = 1024
-
 func newStack() *stack {
 	return &stack{}
 }