Add FloatInst method implementations and tests

FloatInst should be fully implemented now and have a suite of tests to
make sure those methods are doing what they should be.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

tests/int.npp.expect

@@ -6,6 +6,8 @@ __add__
 2419
 30
 30
+-10
+10
 __sub__
 -1
 1
@@ -32,6 +34,21 @@ __div__
 0
 0
 2
+__ne__
+false
+true
+false
+true
+true
+true
+true
+__eq__
+true
+false
+true
+false
+false
+false
 __gt__
 false
 true