patch for mac CI

[tlikhomanenko]

• update theanets to 0.7.3;
• fix theano version 0.8.2 (depend on nose-parameterized -> add to requirements);
• error in import root:
  • without xz ROOT gives:
 Incompatible library version: libCore.so requires version 8.0.0 or later, but liblzma.5.dylib provides version 6.0.0
  • try to solve by https://github.com/Homebrew/legacy-homebrew/issues/42209 installing xz
  • add brew install xz
• remove brew install python (brew install root now doesn't install python from brew -> PyROOT depends on system python, this can be check by otool -L $(brew --prefix root)/lib/root/libPyROOT.so).
• With non system python PyROOT will work if do the following:

brew install python;
brew install root;
sudo install_name_tool -change /System/Library/Frameworks/Python.framework/Versions/2.7/Python /usr/local/Frameworks/Python.framework/Versions/2.7/Python $(brew --prefix root)/lib/root/libPyROOT.so;

[arogozhnikov]

Ok, travis + mac works ok now. Thank you!