Add better error messages for missing dependencies.

If we run into issues importing well-known requirements, report them specially and guide
users on how to install those on their system.

Change-Id: Ic8e4107591198cec8f3744c728bbd23ad5580fba
Fixes: 38004607
Test: manual
diff --git a/tools/hidl_parser/parser.py b/tools/hidl_parser/parser.py
index 79a8608..3096804 100644
--- a/tools/hidl_parser/parser.py
+++ b/tools/hidl_parser/parser.py
@@ -25,6 +25,8 @@
 
 # It requires 'ply' (Python Lex/Yacc).
 
+from __future__ import print_function
+
 import ply
 
 tokens = ('package', 'import', 'enum', 'struct',