Clean up stack file

Removed alex/happy as build-deps, if needed they can be installed with
`stack install alex happy`

stack.yaml

@@ -1,27 +1,16 @@
 resolver: lts-11.22 # ghc 8.2.2
 
 packages:
-- .
-- src/server
-# - src/tools
-- src/runtime/haskell
-# - src/pgf-binary
-- src/runtime/haskell-bind
+- . # GF, PGF
+- src/runtime/haskell-bind # PGF2 (requires C runtime to be installed)
 
 extra-deps:
-- happy-1.19.9
-- alex-3.2.4
-- cgi-3001.3.0.2 # gf, gf-server
-# - fastcgi-3001.0.2.4 # gf-server
-- httpd-shed-0.4.0.3 # gf, gf-server
+# - happy-1.19.9
+# - alex-3.2.4
+- cgi-3001.3.0.2
+- httpd-shed-0.4.0.3
 - time-1.6.0.1 # cgi-3001.3.0.2: time-1.8.0.2 from stack configuration does not match >=1.5 && <1.7
 
-# Override default flag values for local packages and extra-deps
 flags:
-  gf-server:
-    fastcgi: false
-#   gf:
-#     server: true
-
-# Allow a newer minor version of GHC than the snapshot specifies
-compiler-check: newer-minor
+  gf:
+    server: true