modify cmake to build nc

- modify structure of CMakeLists.txt under apps/
  * move apps/CMakeLists.txt to apps/openssl/ since this is for openssl build
  * create new apps/nc/CMakeLists.txt for nc build
  * modify apps/CMakeLists.txt just add_subdirectory()

- add checking and compile of arc4random_uniform()

- add installing man files, openssl.1 and nc.1

apps/nc/Makefile.am

@@ -9,6 +9,7 @@ noinst_PROGRAMS = nc
 endif
 
 EXTRA_DIST = nc.1
+EXTRA_DIST += CMakeLists.txt
 
 nc_LDADD = $(PLATFORM_LDADD) $(PROG_LDADD)
 nc_LDADD += $(top_builddir)/crypto/libcrypto.la