add version.py module exporting '__version__' using metadata from pkg_resources

Do not export 'version' from top-level fontTools.__init__ module, as it is
rarely used; importing pkg_resources here would slow down importing fontTools.

Lib/fontTools/__init__.py

@@ -5,6 +5,4 @@ from fontTools.misc.loggingTools import configLogger
 
 log = logging.getLogger(__name__)
 
-version = "3.0"
-
-__all__ = ["version", "log", "configLogger"]
+__all__ = ["log", "configLogger"]

Lib/fontTools/version.py

@@ -0,0 +1,4 @@
+try:
+	__version__ = __import__('pkg_resources').require('fontTools')[0].version
+except Exception:
+	__version__ = 'unknown'