Added function icl::unit_closure. Enabled functions find, contains and intersects for element-types-arguments on icl containers. Added some tests.

[SVN r69401]

libs/icl

@@ -1 +1 @@
-Subproject commit f30ccbabfebd6e8d3bfd310313c7812e7a6cd3f5
+Subproject commit 86ff9c3dcc0fd289f98e7c053e97792adf3ea93d