Problem: Cumbersome to compile the labs

Solution: Changed the autotools configuration

Prerequisites: libczmq is installed

Step 1: ./configure --enable-labs=yes
Step 2: make
Step 3: make install

Now you've got a library libczmq_labs installed on your system which
can be used in third party projects.

Known issues: Couldn't get czmq_labs_selftest to compile, thus those parts are comments.