set .GlobalEnv during execution
set .GlobalEnv during execution

maybe fixes #61

ibm-et/IRkernel,rgbkrk/IRkernel,gdtm86/IRkernel,JanSchulz/IRkernel,mikecroucher/IRkernel,elaOnMars/IRkernel,Phobia0ptik/IRkernel,ibm-et/IRkernel,ChinaQuants/IRkernel,chendaniely/IRkernel