Fix search parser

Allow + or - in the search string as long as it is not preceeded by
a space. If it is preceeded by a space, it starts a new search
constraint.

src/lua/parser_search.lua

@@ -41,7 +41,7 @@ local fields
 local grammar = P{
 	"chunk";
 	whitespace = S" \t\n"^0,
-	itm = C(P(1-S"+-")^0), --go until the next '+' or '-'
+	itm = C((P(1 - (P" " * S"+-")))^0), --go until the next '+' or '-'
 	likefield = C(P"title" + P"author") * V"whitespace" * C(P"=") * V"whitespace" * V"itm",
 	rangeop = P"<=" + P">=" + P">" + P"<" + P"=",
 	rangefield = C(P"date" + P"hits") * V"whitespace" * C(V"rangeop") * V"whitespace" * C(V"itm"),
@@ -54,7 +54,7 @@ local grammar = P{
 			table.insert(fields.tags,{pn,"=",field})
 		end
 	end,
-	chunk = V"field"^0
+	chunk = V"field" * (P" " * V"field")^0
 
 }
 --Grammar