remove version pinning from setup.py

setup.py

@@ -21,22 +21,22 @@ setup(name='freqtrade',
       setup_requires=['pytest-runner'],
       tests_require=['pytest', 'pytest-mock', 'pytest-cov'],
       install_requires=[
-          'python-bittrex==0.2.0',
-          'SQLAlchemy==1.1.13',
-          'python-telegram-bot==8.1.1',
-          'arrow==0.10.0',
-          'requests==2.18.4',
-          'urllib3==1.22',
-          'wrapt==1.10.11',
-          'pandas==0.20.3',
-          'scikit-learn==0.19.0',
-          'scipy==0.19.1',
-          'jsonschema==2.6.0',
-          'TA-Lib==0.4.10',
-          'tabulate==0.8.1',
+          'python-bittrex',
+          'SQLAlchemy',
+          'python-telegram-bot',
+          'arrow',
+          'requests',
+          'urllib3',
+          'wrapt',
+          'pandas',
+          'scikit-learn',
+          'scipy',
+          'jsonschema',
+          'TA-Lib',
+          'tabulate',
       ],
       dependency_links=[
-          "git+https://github.com/ericsomdahl/python-bittrex.git@0.2.0#egg=python-bittrex-0.2.0"
+          "git+https://github.com/ericsomdahl/python-bittrex.git@0.2.0#egg=python-bittrex"
       ],
       include_package_data=True,
       zip_safe=False,