update constants (Uniswap#13)

Author: NoahZinsmeister

src/constants.ts

@@ -1,7 +1,7 @@
 import JSBI from 'jsbi'
 
-export const MSG_SENDER = '0x0000000000000000000000000000000000000000'
-export const ADDRESS_THIS = '0x0000000000000000000000000000000000000001'
+export const MSG_SENDER = '0x0000000000000000000000000000000000000001'
+export const ADDRESS_THIS = '0x0000000000000000000000000000000000000002'
 
 export const ZERO = JSBI.BigInt(0)
 export const ONE = JSBI.BigInt(1)