Make bin/rho path-independent (#32)

Find the source directory based on sys.argv[0], rather than a
hardcoded path from a specific developer's machine. Fixes issues/31.

bin/rho

@@ -11,9 +11,14 @@
 #
 
 import gettext
+import os
 import sys
 
-sys.path.insert(0, '/home/kbattula/devel/rho2/src')
+base_rho_directory = os.path.abspath(
+  os.path.normpath(
+    os.path.join(
+      os.path.dirname(sys.argv[0]), '..')))
+sys.path.insert(0, os.path.join(base_rho_directory, 'src'))
 
 from rho.cli import CLI