drop support of python 3.4

.travis.yml

 sudo: false
 language: python
 python:
-  - "3.4"
   - "3.5"
   - "3.6"
 

README.md

 
 Hapic is under active development, based on Algoo projects. We will answer your questions and accept merge requests if you find bugs or want to include functionnalities.
 
+Hapic is currently tested on python 3.5 and 3.6.
+
 ## TODO references
 
 TODO can make reference to #X, this is github issues references.
 - managing output schema
 - management of error cases (404, 500, etc)
 - nice exception handling
-- automatic dict/object serialization
+- automatic dict/object serialization