Improved support for GNU/kFreeBSD

- add kFreeBSD to NBI and CPUID
- add kFreeBSD to jcpuid/jbigi build scripts
- refresh debian patches to compensate for kFreeBSD changes
- i2prouter: Detect kFreeBSD and normalize its name
- clean up osid (switching to "elif") and adding support for detecting kFreeBSD
- update postinstall.sh; I2P cannot be installed using gij so postinstall.sh
  will not be run. If/when openjdk finally comes to kFreeBSD, we'll be ready for it.

debian/patches/0003-renaming-jcpuid.patch

@@ -8,12 +8,16 @@ Subject: rename jcpuid
 
 --- a/core/c/jcpuid/build.sh
 +++ b/core/c/jcpuid/build.sh
-@@ -65,8 +65,8 @@
-                 exit 1;;
+@@ -67,12 +67,8 @@
+                 exit 0;;
          esac
  
 -        LINKFLAGS="-shared -Wl,-soname,libjcpuid-${ARCH}-${UNIXTYPE}.so"
--        LIBFILE="lib/freenet/support/CPUInformation/libjcpuid-${ARCH}-${UNIXTYPE}.so"
+-        if [ $KFREEBSD -eq 1 ]; then
+-            LIBFILE="lib/freenet/support/CPUInformation/libjcpuid-${ARCH}-kfreebsd.so"
+-        else
+-            LIBFILE="lib/freenet/support/CPUInformation/libjcpuid-${ARCH}-${UNIXTYPE}.so"
+-        fi
 +        LINKFLAGS="-shared -Wl,-soname,libjcpuid.so"
 +        LIBFILE="../jbigi/libjcpuid.so"
          COMPILEFLAGS="-fPIC -Wall"