Removed strict dependencies.

We are about to find general a solution for pinning to ABIs [here](conda/conda-build#728 (comment)).

recipes/openbabel/2.3.2/meta.yaml

@@ -5,27 +5,33 @@ about:
     of chemical data. It''s an open, collaborative project allowing anyone to search,
     convert, analyze, or store data from molecular modeling, chemistry, solid-state
     materials, biochemistry, or related areas.'
+
 build:
+  skip: True # [not py27]
   number: 1
+
 package:
   name: openbabel
   version: 2.3.2
+
 requirements:
   build:
-  - python  [not py3k]
-  - gcc     [not win]
-  - cmake ==3.2.3
-  - eigen ==3.1.3
-  - libxml2 ==2.9.3
-  - zlib ==1.2.8
-  - cairo ==1.12.18
+  - python
+  - gcc
+  - cmake
+  - eigen
+  - libxml2
+  - zlib
+  - cairo
   run:
-  - python  [not py3k]
+  - python
   - libgcc
+
 source:
   fn: openbabel-2.3.2.tar.gz
   sha256: 4eaca26679aa6cc85ebf96af19191472ac63ca442c36b0427b369c3a25705188
   url: http://downloads.sourceforge.net/project/openbabel/openbabel/2.3.2/openbabel-2.3.2.tar.gz
+
 test:
   commands:
   - obabel --help