Fix the C++ exception struct in nimbase.h.
Fix the C++ exception struct in nimbase.h.

The struct NimException still referred to the old exception type
E_Base, which has since been renamed to Exception. This made the
C++ backend fail on any code that used exceptions.

nimLuckyBull/Nim,sferik/Nim,BlaXpirit/nim,sferik/Nim,douglas-larocca/Nim,SSPkrolik/Nim,sferik/Nim,dom96/Nim,tulayang/Nim,SSPkrolik/Nim,msmith491/Nim,jsanjuas/Nim,nanoant/Nim,tulayang/Nim,Salafit/Nim,tmm1/Nim,Matt14916/Nim,fmamud/Nim,nimLuckyBull/Nim,sferik/Nim,sarvex/Nim-lang,dom96/Nim,nanoant/Nim,nafsaka/Nim,Dhertz/Nim,tmm1/Nim,fredericksilva/Nim,fmamud/Nim,msmith491/Nim,nanoant/Nim,Senketsu/Nim,greyanubis/Nim,judofyr/Nim,fredericksilva/Nim,Salafit/Nim,MrJohz/Nim,mbaulch/Nim,BlaXpirit/nim,endragor/Nim,nimLuckyBull/Nim,kirbyfan64/Nim,fredericksilva/Nim,tmm1/Nim,fmamud/Nim,kirbyfan64/Nim,MrJohz/Nim,sferik/Nim,MrJohz/Nim,douglas-larocca/Nim,gokr/Nim,nanoant/Nim,sarvex/Nim-lang,xland/Nim,jsanjuas/Nim,haiodo/Nim,nimLuckyBull/Nim,judofyr/Nim,sarvex/Nim-lang,SSPkrolik/Nim,haiodo/Nim,mbaulch/Nim,greyanubis/Nim,reactormonk/nim,singularperturbation/Nim,JCavallo/Nim,bvssvni/Nim,tulayang/Nim,mbaulch/Nim,zachaysan/Nim,BlaXpirit/nim,kirbyfan64/Nim,MrJohz/Nim,russpowers/Nim,nimLuckyBull/Nim,reactormonk/nim,haiodo/Nim,Dhertz/Nim,fredericksilva/Nim,tmm1/Nim,Dhertz/Nim,Senketsu/Nim,nafsaka/Nim,Salafit/Nim,mbaulch/Nim,JCavallo/Nim,singularperturbation/Nim,gokr/Nim,gokr/Nim,SSPkrolik/Nim,douglas-larocca/Nim,mbaulch/Nim,jfhg/Nim,Matt14916/Nim,Dhertz/Nim,Matt14916/Nim,judofyr/Nim,mbaulch/Nim,bvssvni/Nim,kirbyfan64/Nim,greyanubis/Nim,JCavallo/Nim,sferik/Nim,Matt14916/Nim,greyanubis/Nim,Senketsu/Nim,Salafit/Nim,bvssvni/Nim,haiodo/Nim,reactormonk/nim,gokr/Nim,nanoant/Nim,nafsaka/Nim,MrJohz/Nim,endragor/Nim,nafsaka/Nim,xland/Nim,nafsaka/Nim,sarvex/Nim-lang,nimLuckyBull/Nim,jsanjuas/Nim,reactormonk/nim,jsanjuas/Nim,gokr/Nim,dom96/Nim,BlaXpirit/nim,haiodo/Nim,jfhg/Nim,reactormonk/nim,fmamud/Nim,reactormonk/nim,bvssvni/Nim,kirbyfan64/Nim,tmm1/Nim,jfhg/Nim,Senketsu/Nim,SSPkrolik/Nim,jfhg/Nim,nafsaka/Nim,kirbyfan64/Nim,haiodo/Nim,xland/Nim,dom96/Nim,gokr/Nim,kirbyfan64/Nim,russpowers/Nim,JCavallo/Nim,dom96/Nim,fredericksilva/Nim,bvssvni/Nim,russpowers/Nim,russpowers/Nim,endragor/Nim,Salafit/Nim,bvssvni/Nim,fredericksilva/Nim,tmm1/Nim,Matt14916/Nim,jfhg/Nim,bvssvni/Nim,Salafit/Nim,SSPkrolik/Nim,greyanubis/Nim,nafsaka/Nim,fmamud/Nim,tmm1/Nim,dom96/Nim,judofyr/Nim,haiodo/Nim,gokr/Nim,douglas-larocca/Nim,judofyr/Nim,kirbyfan64/Nim,JCavallo/Nim,dom96/Nim,zachaysan/Nim,jsanjuas/Nim,reactormonk/nim,nanoant/Nim,xland/Nim,endragor/Nim,sarvex/Nim-lang,Dhertz/Nim,SSPkrolik/Nim,jfhg/Nim,fmamud/Nim,Senketsu/Nim,msmith491/Nim,xland/Nim,Dhertz/Nim,xland/Nim,msmith491/Nim,zachaysan/Nim,Senketsu/Nim,Senketsu/Nim,sferik/Nim,BlaXpirit/nim,zachaysan/Nim,fredericksilva/Nim,zachaysan/Nim,fredericksilva/Nim,greyanubis/Nim,endragor/Nim,Dhertz/Nim,endragor/Nim,douglas-larocca/Nim,Salafit/Nim,judofyr/Nim,JCavallo/Nim,tulayang/Nim,nanoant/Nim,russpowers/Nim,MrJohz/Nim,douglas-larocca/Nim,nimLuckyBull/Nim,BlaXpirit/nim,sferik/Nim,jsanjuas/Nim,zachaysan/Nim,jfhg/Nim,douglas-larocca/Nim,judofyr/Nim,MrJohz/Nim,Matt14916/Nim,gokr/Nim,reactormonk/nim,douglas-larocca/Nim,greyanubis/Nim,endragor/Nim,Matt14916/Nim,msmith491/Nim,singularperturbation/Nim,singularperturbation/Nim,russpowers/Nim,SSPkrolik/Nim,sarvex/Nim-lang,singularperturbation/Nim,judofyr/Nim,xland/Nim,mbaulch/Nim,msmith491/Nim,jsanjuas/Nim,fmamud/Nim,singularperturbation/Nim,singularperturbation/Nim,tulayang/Nim,sarvex/Nim-lang,BlaXpirit/nim,tulayang/Nim,JCavallo/Nim,zachaysan/Nim,russpowers/Nim,msmith491/Nim,BlaXpirit/nim