layout files: add the new AllowedPlacement

lib/layouts/powerdot.layout

@@ -496,6 +496,55 @@ Style Pause
   EndFont
 End
 
+###
+# Float definitions
+###
+Float
+	Type                  table
+	GuiName               Table
+	Placement             tbp
+	AllowedPlacement      H
+	Extension             lot
+	NumberWithin          none
+	Style                 plain
+	ListName              "List of Tables"
+	IsPredefined          true
+	UsesFloatPkg          false
+	ListCommand           listoftables
+	RefPrefix             tab
+End
+
+
+Float
+	Type                  figure
+	GuiName               Figure
+	Placement             tbp
+	AllowedPlacement      H
+	Extension             lof
+	NumberWithin          none
+	Style                 plain
+	ListName              "List of Figures"
+	IsPredefined          true
+	UsesFloatPkg          false
+	ListCommand           listoffigures
+	RefPrefix             fig
+End
+
+
+Float
+	Type                  algorithm
+	GuiName               Algorithm
+	Placement             tbp
+	AllowedPlacement      H
+	Extension             loa
+	NumberWithin          none
+	Style                 ruled
+	ListName              "List of Algorithms"
+	IsPredefined          false
+	UsesFloatPkg          true
+	RefPrefix             alg
+End
+
 ###
 # Counters definitions
 ###

lib/layouts/sciposter.layout

@@ -86,6 +86,7 @@ Float
 	Type                  algorithm
 	GuiName               Algorithm
 	Placement             tbp
+	AllowedPlacement      !htbp
 	Extension             loa
 	NumberWithin          none
 	Style                 none

lib/layouts/tufte-book.layout

@@ -227,6 +227,7 @@ Float
 	Type			margintable
 	GuiName			MarginTable
 	Placement		tbp
+	AllowedPlacement none
 	Extension		lot
 	NumberWithin	none
 	Style			plain
@@ -240,6 +241,7 @@ Float
 	Type			marginfigure
 	GuiName			MarginFigure
 	Placement		tbp
+	AllowedPlacement none
 	Extension		lof
 	NumberWithin	none
 	Style			plain