Simple improvements to function calls

[justinethier]

A few simple improvements can be made:

• If an invalid form (probably not a symbol or list) is found in the function position, an error should be thrown at compile time
• If an atom is found in the function position, it should be possible to inline it and avoid creating a wrapper function at runtime.

This is closely related to the other ticket on streamlining generated code since targeting function compilation is the best way to improve the compiler at this point.

[justinethier]

Another thought - would explicit type signatures improve compile times?

[justinethier]

Added explicit type signatures for a modest speed improvement.

compileAllArgs func' needs to be updated to inline the function portion, if it is an Atom. In addition, this function should be able to be modified to append literal args directly to args, instead of creating unnecessary wrapper functions.

[justinethier]

Test case for previous commit:

(list `(list ,(+ 1 2) 4)
  '(list 3 4)) 

> Expected 2 args; found values list

[justinethier]

Previous issues are fixed up, but now there is another problem:

(define (assv obj alist)
    (foldl (mem-helper (curry eqv? obj) car) #f alist))   
(assv 'b '((a 1)))

foldl should receive args of #f ((a 1)) but gets mem-helper instead of #f.

Should compare generated hs code in both cases.