refactor(cc-mode): redesign for loop snippets

- Changes former 'fori' snippet to 'forit' for iterator loop.
- Changes 'fre' to 'fore' for std::for_each loop.
- Adds 'fori' snippet for a typical indexed for-loop.
- Simplifies basic 'for' loop.

I'll add sub-snippets later so users can expand certain idioms within
the for loop arguments or body.

Close: #91

Author: hlissner

c++-mode/for_each

@@ -1,6 +1,7 @@
 # -*- mode: snippet -*-
-# name: for_each
-# key: fre
+# name: for each loop
+# key: fore
+# uuid: fore
 # --
 std::for_each(std::begin(${1:container}), std::end($1), []($2) {
   `%`$3

c++-mode/for_iter renamed to c++-mode/for_iterator

@@ -1,8 +1,8 @@
 # -*- mode: snippet -*-
-# name: for_iter
-# key: fori
-# uuid: fori
+# name: for iterator loop
+# key: forit
+# uuid: forit
 # --
 for (${1:iter}=${2:var}.begin(); $1!=$2.end(); ++$1) {
-    $0
+    `%`$0
 }

cc-mode/for

@@ -3,6 +3,6 @@
 # key: for
 # uuid: for
 # --
-for (${1:i = 0}; ${2:i < N}; ${3:i++}) {
-    $0
+for ($1; $2; $3) {
+    `%`$0
 }

cc-mode/fori

@@ -0,0 +1,8 @@
+# -*- mode: snippet -*-
+# name: fori
+# key: fori
+# uuid: fori
+# --
+for (${1:int} ${2:i} = 0; $2 < ${3:length}; $2++}) {
+    `%`$0
+}