[Serializer] Add a new class.
[HatoholArmPluginInterface] Convert data to L.E.

With New plugin achitecture, plugin process can run on a remote
commputer. So they might use different byte order. Hapi uses
little endian in the packet.

Actually, it's not needed to convert data on i386 and x86.
Probably LtoN() and NtoL() will be zero overhead.
[server] User a more suitable name.

Serializer ->
EndianConverter
[HatoholArmPluginInterface] Add structures to send ItemDataTable.
[HatoholArmPluginBase] Add a stub method: sendUpdatedTriggers().
[mlpl][SmartBuffer] Add an API description.
[HatoholArmPluginInterface] Add a new method: appendItemData().
[testHatoholArmPluginInterface] Add a test: test_appendItemBool().
[HatoholArmPluginInterface] Fix a build error on Ubuntu 12.04 with clang.

The following message was shown.

HatoholArmPluginInterface.cc:295:31: error: invalid use of non-static data
      member 'length'
              sizeof(HapiItemStringHeader::length),
Merge pull request #225 from project-hatohol/issue-171-5a

Issue 171 5a