Codegen: General improvements. (#1379)
Codegen: General improvements. (#1379)

- Support more C(-like) statements and expressions.
- Better variable pretty-printing.
- Better function call argument parsing. Now we print out strings instead
  of constant integers for char* arguments of a function call.
- Other minor improvements that I did not keep track of.
iamahuman/angr,schieb/angr,angr/angr,iamahuman/angr,schieb/angr,angr/angr,schieb/angr,iamahuman/angr,angr/angr