Add travis.yml and requirements.txt

- these are very minimalistic, with input from @g1itch, @sigoa and
  @venkateshpitta

.travis.yml

@@ -0,0 +1,6 @@
+language: python
+python:
+        - "2.7"
+install:
+        - pip install -r requirements.txt
+script: src/bitmessagemain.py -t

requirements.txt

@@ -0,0 +1,6 @@
+setuptools
+numpy
+PyQt4
+gi
+msgpack_python
+pyopencl