travis: update to clang-3.6 and gcc-4.9 and set env variables properly
travis: update to clang-3.6 and gcc-4.9 and set env variables properly

dckc/ponyc,ryanai3/ponyc,Perelandric/ponyc,lukecheeseman/ponyta,jupvfranco/ponyc,mkfifo/ponyc,Theodus/ponyc,Praetonus/ponyc,jemc/ponyc,boemmels/ponyc,dipinhora/ponyc,Perelandric/ponyc,mkfifo/ponyc,Praetonus/ponyc,cquinn/ponyc,lukecheeseman/ponyta,Theodus/ponyc,CausalityLtd/ponyc,boemmels/ponyc,ponylang/ponyc,boemmels/ponyc,pap/ponyc,Theodus/ponyc,doublec/ponyc,Perelandric/ponyc,mkfifo/ponyc,pap/ponyc,malthe/ponyc,malthe/ponyc,darach/ponyc,Theodus/ponyc,boemmels/ponyc,jonas-l/ponyc,Perelandric/ponyc,ponylang/ponyc,mkfifo/ponyc,sgebbie/ponyc,dipinhora/ponyc,sgebbie/ponyc,Perelandric/ponyc,cquinn/ponyc,jupvfranco/ponyc,ryanai3/ponyc,kulibali/ponyc,cquinn/ponyc,Theodus/ponyc,dckc/ponyc,jonas-l/ponyc,boemmels/ponyc,dipinhora/ponyc,malthe/ponyc,doublec/ponyc,mkfifo/ponyc,doublec/ponyc,lukecheeseman/ponyta,malthe/ponyc,darach/ponyc,jemc/ponyc,Praetonus/ponyc,CausalityLtd/ponyc,pap/ponyc,kulibali/ponyc,kulibali/ponyc,darach/ponyc,jupvfranco/ponyc,sgebbie/ponyc,sgebbie/ponyc,jupvfranco/ponyc,ponylang/ponyc,jupvfranco/ponyc,CausalityLtd/ponyc,Praetonus/ponyc,jonas-l/ponyc,kulibali/ponyc,cquinn/ponyc,jemc/ponyc,sgebbie/ponyc,ryanai3/ponyc