add fix for qt moc BOOST_JOIN problem for osx yosemite build

[kpykc]

Solution for problem with Qt moc generator and BOOST_JOIN:

Generating include/octomap_rviz_plugins/moc_occupancy_grid_display.cxx
usr/local/Cellar/boost/1.56.0/include/boost/type_traits/detail/has_binary_operator.hp:50: Parse error at "BOOST_JOIN"
make[3]: *** [extern/octomap_rviz_plugins/include/octomap_rviz_plugins/moc_occupancy_map_display.cxx] Error 1

I faced with this problem during build on ros/indigo+rviz/hydro+osx/yosemite+homebrew/boost:

$ brew info boost
boost: stable 1.56.0 (bottled), HEAD
http://www.boost.org
/usr/local/Cellar/boost/1.56.0 (10471 files, 438M) *
Poured from bottle
From: https://github.com/Homebrew/homebrew/blob/master/Library/Formula/boost.rb

$ brew config
HOMEBREW_VERSION: 0.9.5
ORIGIN: https://github.com/Homebrew/homebrew
HEAD: 32923f435c7cf93820f434d6bdacf3bfdc3695eb
Last commit: 2 months ago
HOMEBREW_PREFIX: /usr/local
HOMEBREW_CELLAR: /usr/local/Cellar
CPU: quad-core 64-bit ivybridge
OS X: 10.10.2-x86_64
CLT: 6.1.1.0.1.1416017670
Clang: 6.0 build 600
X11: 2.7.7 => /opt/X11
System Ruby: 2.0.0-481
Perl: /usr/bin/perl
Python: /usr/local/bin/python => /usr/local/Cellar/python/2.7.8_2/Frameworks/Python.framework/Versions/2.7/bin/python2.7
Ruby: /usr/bin/ruby

-DBOOST_LEXICAL_CAST_INCLUDED option for QT4_WRAP_CPP seems to be needed too for successful build. By analogy with this commit https://github.com/ros-visualization/rviz/pull/589