Handle Multi-Line Functions

[gibiansky]

Currently, defining a function on multiple lines causes only the last definition to hold:

f 3 = 2
f 2 = 3

f 2 -- returns 3
f 3 -- errors out

This is the same thing that GHCi does. However, it should be possible to detect that consecutive statements are defining the same function and join them.

[gibiansky]

Should now be handled properly, fixed in commit e02e5c2

The handling is rather sketchy and their may be edge cases that cause everything to break.