Added list comprehensions and standard List, Option, Func, Pair, and Triple library (#105)

* Added standard List library and list comprehensions

Added List library.

Flatmaps WIP

Fixed dependency in flat_map

fcode generation

Updated tests to use custom list lib

Added comprehension test

Added stdlib

sanity

Test

* Extended stdlib for lists. Added error message for redefinition of stdlibx

* Fixed type template

* Improved stdlib

* More functions

* Fixed cyclic includes

* Refixed imports and added few tests

* Added fail test

* Undelete removed type spec

* Remove typo

* Fix iter function

* Fixed typo

* Added if guards and let statements in list comp

* Added more fail tests

* Option stliv

* 2 and 3 tuple stdlib

* Updated stdlib to new syntax. Added recursor and changed all/any functions

* Fixed performance issues. Changed include management

* Fixed hash type

test/contracts/list_comp.aes

@@ -0,0 +1,23 @@
+contract ListComp =
+
+    entrypoint sample1() = [1,2,3]
+    entrypoint sample2() = [4,5]
+
+    entrypoint l1() = [x | x <- sample1()]
+    entrypoint l1_true() = [1,2,3]
+
+    entrypoint l2() = [x + y | x <- sample1(), y <- sample2()]
+    entrypoint l2_true() = [5,6,6,7,7,8]
+
+    entrypoint l3() = [x ++ y | x <- [[":)"] | x <- [1,2]]
+                              , y <- [[":("]]]  
+    entrypoint l3_true() = [[":)", ":("], [":)", ":("]]
+
+    entrypoint l4() = [(a, b, c) | let is_pit(a, b, c) = a*a + b*b == c*c
+                                 , let base = [1,2,3,4,5,6,7,8,9,10]
+                                 , a <- base
+                                 , b <- base, if (b >= a)
+                                 , c <- base, if (c >= b)
+                                 , if (is_pit(a, b, c))
+                                 ]
+    entrypoint l4_true() = [(3, 4, 5), (6, 8, 10)]