libsepol: Move secilc out of libsepol

Since the secilc compiler is independent of libsepol, move secilc out of
libsepol. Linke secilc dynamically rather than statically with libsepol.

- Move secilc source, test policies, docs, and secilc manpage to secilc
  directory.
- Remove unneeded Makefile from libsepol/cil. To build secilc, run make
  in the secilc directory.
- Add target to install the secilc binary to /usr/bin/.
- Create an Android makefile for secilc and move secilc out of libsepol
  Android makefile.
- Add cil_set_mls to libsepol public API as it is needed by secilc.
- Remove policy.conf from testing since it is no longer used.

Signed-off-by: Yuli Khodorkovskiy <ykhodorkovskiy@tresys.com>
diff --git a/Makefile b/Makefile
index f71faab..93e10de 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-SUBDIRS=libsepol libselinux libsemanage sepolgen checkpolicy policycoreutils # policy
+SUBDIRS=libsepol libselinux libsemanage sepolgen checkpolicy secilc policycoreutils # policy
 PYSUBDIRS=libselinux libsemanage
 DISTCLEANSUBIDRS=libselinux libsemanage