Slang3 problem set. 

0) Download slang3/vsm2, compiler, and run examples. 
   Write Slang3 code and test the compiler. 
   Report bugs and enjoy Kit-Kat bars. 
1) Add strings as a basic datatype. 
2) Add records. 
3) Add disjoint union (inl _, inr _, etc) to Slang3. 
4) Write a simple garbage collector (in C) for VSM.2. 
5) Add objects. 
6) Add tuples. But be careful. This requires a change 
   to the way functions are currently implemented. 
7) Extend equality. Currently equality works only 
   for integer types. Can you extend this to all
   types?  What does function equality mean? 
8) Add exceptions. 
9) From IR2, generate code for a register-oriented 
   machine of your choice.