Improve libnite

[ipa-nhg]

• remove the libnite2/build folder after building libnite package.

+1, the build folder should be deleted

• The ".so" files are in devel/lib and in src/.../libnite2/common/lib. We should keep them in a single directory.

for me is ok keep them, but if you prefer delete the src/.../libnite2/common/lib/*.so after build , I have nothing against

• Idid not understand the catkin_RUN_PACKAGES and catkin_BUILD_PACKAGES variable in libnite2/CMakeLists.txt and squirrel_person_tracker/CMakeLists.txt.
  You set the value in squirrel_person_tracker/CMakeLists.txt to:
  catkin_RUN_PACKAGES -> package_name(libnite2)
  catkin_BUILD_PACKAGES -> libnite2cmake_modules
  I don't see the purpose of this. What is libnite2cmake_modules doing anyway in find package???
  Why we don't use simple package name.

I used the variables just to test, but now, if you prefer use the package names and delete the variables, you can do it. Are not needed