update package manifest to format 2
Merge pull request #619 from ros/package_format_2

update package manifest to format 2
Export architecture_independent flag in package.xml
Merge pull request #625 from cottsay/indigo-devel

Export architecture_independent flag in package.xml
update travis config to use debian python and install mock
Merge pull request #628 from ros/test_travis

work around travis using non-debian Python by default
part of #304 create a workspace marker file when build succeeded.
Requires catkin_pgk 0.2.2
Merge pull request #603 from tkruse/search_base

Marker file for catkin_make (#304)
set catkin_* variables only when find_package(catkin COMPONENTS ...)
allow better performance for repeated invocations of find_in_workspaces()
Merge pull request #629 from ros/cmake_config_set_variable_only_for_components

Only set catkin_* variables when being invoked with find_package COMPONENTS
Implement multiarch support in catkin (#545)

This implements multiarch support (#545), and supercedes
(#604). A two step approach uses gcc -print-multiarch and,
if failed, fallback to use dpkg-architecture to identify
an appropriate lib folder suffix to use for LD_LIBRARY_PATH
and PKG_CONFIG_PATH. builder.py and
catkin_generate_environment.cmake are modified
accordingly.

Thanks to @j-rivero for his contributions, which are hidden in
this squashed commit.