added reset_seed

docs/scarpet/language/SystemFunctions.md

@@ -239,6 +239,11 @@ map(range(10), bool(rand(2))) => [false, false, true, false, false, false, true,
 map(range(10), str('%.1f',rand(_))) => [0.0, 0.4, 0.6, 1.9, 2.8, 3.8, 5.3, 2.2, 1.6, 5.6]
 </pre>
 
+## `reset_seed(seed)`
+
+Resets the sequence of the randomizer used by `rand` for this seed to its initial state. Returns a boolean value
+indicating if the given seed has been used or not.
+
 ### `perlin(x), perlin(x, y), perlin(x, y, z), perlin(x, y, z, seed)`
 
 returns a noise value from `0.0` to `1.0` (roughly) for 1, 2 or 3 dimensional coordinate. The default seed it samples 

docs/scarpet/resources/editors/idea/1.txt

@@ -63,6 +63,7 @@ reduce
 relu
 replace
 replace_first
+reset_seed
 return
 round
 sec

docs/scarpet/resources/editors/npp/scarpet.xml

@@ -25,7 +25,7 @@
             <Keywords name="Folders in comment, middle"></Keywords>
             <Keywords name="Folders in comment, close"></Keywords>
             <Keywords name="Keywords1">
-                not fact rand
+                not fact rand reset_seed
                 sin cos tan asin acos atan atan2 sinh cosh tanh sec csc sech csch cot acot coth asinh acosh atanh
                 rad deg
                 log log10 log1p
@@ -46,7 +46,7 @@
 
                 var undef vars if loop map filter first all c_for for while reduce continue break
 
-                import call outer type hash_code bool number str length rand sleep time profile_expr lower upper title replace replace_first
+                import call outer type hash_code bool number str length sleep time profile_expr lower upper title replace replace_first
             </Keywords>
             <Keywords name="Keywords2">
                 block pos pos_offset solid air liquid flammable