Stabilize requirements.txt

- Setuptools shouldn't be included
- Bump numpy version due to build error on Linux
- Bump all dependencies for compatability
- Freeze all (sub-)dependency versions

requirements.txt

@@ -1,5 +1,13 @@
-setuptools
-ascii_graph==1.2.0
-tqdm==4.11.2
-numpy==1.12.0
-tweepy==3.5.0
+ascii-graph==1.5.1
+certifi==2018.8.24
+chardet==3.0.4
+idna==2.7
+numpy==1.15.1
+oauthlib==2.1.0
+PySocks==1.6.8
+requests==2.19.1
+requests-oauthlib==1.0.0
+six==1.11.0
+tqdm==4.25.0
+tweepy==3.6.0
+urllib3==1.23