removed robotframework from requirements.txt and added additional dependency checks to robottools/__init__.py instead

--HG--
branch : dev

Author: userzimmermann

requirements.txt

@@ -3,5 +3,3 @@ six >= 1.10
 path.py >= 8.0 #import path
 moretools >= 0.1.8
 modeled >= 0.1.8
-#py2 robotframework >= 2.8.7 #import robot
-#py3 robotframework-python3 >= 2.8.7 #import robot

robottools/__init__.py

@@ -25,6 +25,7 @@
 """
 
 from zetup import find_zetup_config
+from zetup.version import Version
 
 zfg = find_zetup_config(__name__)
 
@@ -38,6 +39,17 @@
 
 ## __notebook__ = zfg.NOTEBOOKS['README']
 
+try:
+    import robot
+except ImportError as exc:
+    raise ImportError(
+        "%s depends on robotframework but import failed with: %s"
+        % (repr(__distribution__), exc))
+if Version(robot.__version__) < '2.8.7':
+    raise __import__('pkg_resources').VersionConflict(
+        "%s needs robotframework>=2.8.7 but found %s in %s"
+        % (repr(__distribution__), robot.__version__, repr(robot)))
+
 from robottools.library import *
 from robottools.library.keywords import *
 from robottools.library.session import SessionHandler